├── .env.dart ├── .gitignore ├── test-driven-dart.pdf ├── .gitattributes ├── .vscode └── settings.json ├── Makefile ├── .github └── workflows │ └── build.yml ├── LICENSE ├── test-driven-dart.tex ├── script.sh ├── 1_Getting_Started ├── 1.3_Basic_Test_Structure.md ├── 1.1_Introduction_to_Testing.md └── 1.2_Setting_Up_Testing_Environment.md ├── CONTRIBUTING.md ├── 7_External_Resources_and_Links ├── 7.3_Related_Communities_and_Forums.md ├── 7.2_Recommended_Books_and_Courses.md └── 7.1_Official_Documentation_and_Guides.md ├── 4_Integration_Tests ├── 4.1_Introduction_to_Integration_Tests.md ├── 4.2_Setting_Up_Integration_Tests.md └── 4.3_Tips_for_Writing_Robust_Integration_Tests.md ├── 2_Unit_Tests └── 2.1_Basics_of_Unit_Testing.md ├── 6_Special_Topics ├── 6.2_BDD_with_Dart.md ├── 6.1_TDD_in_Dart.md └── 6.3_Performance_Testing.md ├── 3_Widget_Tests ├── 3.1_Introduction_to_Widget_Tests.md ├── 3.3_Testing_Individual_Widgets.md ├── 3.2_Mocking_Widgets.md └── 3.4_Advanced_Widget_Testing_Topics.md ├── 5_Testing_Tips_and_Best_Practices ├── 5.3_Common_Pitfalls_and_How_to_Avoid_Them.md ├── 5.1_Organizing_Test_Code.md └── 5.2_Continuous_Integration_and_Dart.md ├── README.md └── tex ├── ch2-unit-tests.tex ├── preamble.tex ├── ch1-getting-started.tex ├── ch4-integration-tests.tex ├── ch7-external-resources-and-links.tex ├── ch6-special-topics.tex ├── ch5-test-tips-and-best-practices.tex └── ch3-widget-tests.tex /.env.dart: -------------------------------------------------------------------------------- 1 | 2 | -------------------------------------------------------------------------------- /.gitignore: -------------------------------------------------------------------------------- 1 | build/ 2 | _minted-test-driven-dart/ 3 | indent.log 4 | tdd.synctex.gz -------------------------------------------------------------------------------- /test-driven-dart.pdf: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/Yczar/test-driven-dart/HEAD/test-driven-dart.pdf -------------------------------------------------------------------------------- /.gitattributes: -------------------------------------------------------------------------------- 1 | *.tex linguist-detectable=false 2 | *.sh linguist-detectable=false 3 | *Makefile linguist-detectable=false 4 | *.pdf linguist-detectable=false 5 | -------------------------------------------------------------------------------- /.vscode/settings.json: -------------------------------------------------------------------------------- 1 | { 2 | "[latex]": { 3 | "editor.wordWrap": "on", 4 | "editor.tabSize": 1 5 | }, 6 | "[latex-expl3]": { 7 | "editor.wordWrap": "on", 8 | "editor.tabSize": 1 9 | }, 10 | "[tex]": { 11 | "editor.wordWrap": "on", 12 | "editor.tabSize": 1 13 | }, 14 | } -------------------------------------------------------------------------------- /Makefile: -------------------------------------------------------------------------------- 1 | PROJECTNAME=test-driven-dart 2 | BUILDDIR=build 3 | 4 | .PHONY: $(PROJECTNAME).pdf all clean 5 | 6 | all: $(PROJECTNAME).pdf 7 | 8 | $(PROJECTNAME).pdf: $(PROJECTNAME).tex 9 | latexmk -pdf -synctex=1 -verbose -bibtex -pvc -shell-escape -interaction=nonstopmode -file-line-error -output-directory=$(BUILDDIR) $< 10 | 11 | clean: 12 | latexmk -output-directory=$(BUILDDIR) -c && rm -rf build/* -------------------------------------------------------------------------------- /.github/workflows/build.yml: -------------------------------------------------------------------------------- 1 | name: Build PDF 2 | 3 | 4 | on: 5 | push: 6 | branches: 7 | - master 8 | 9 | jobs: 10 | build_latex: 11 | runs-on: ubuntu-latest 12 | steps: 13 | - name: Set up Git repository 14 | uses: actions/checkout@v3 15 | - name: Compile LaTeX document 16 | uses: xu-cheng/latex-action@v2 17 | with: 18 | root_file: test-driven-dart.tex 19 | latexmk_use_lualatex: true 20 | latexmk_shell_escape: true 21 | args: "-outdir=build" -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | MIT License 2 | 3 | Copyright (c) 2023 Babalola Ayotomide 4 | 5 | Permission is hereby granted, free of charge, to any person obtaining a copy 6 | of this software and associated documentation files (the "Software"), to deal 7 | in the Software without restriction, including without limitation the rights 8 | to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 9 | copies of the Software, and to permit persons to whom the Software is 10 | furnished to do so, subject to the following conditions: 11 | 12 | The above copyright notice and this permission notice shall be included in all 13 | copies or substantial portions of the Software. 14 | 15 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 16 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 17 | FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 18 | AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 19 | LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 20 | OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 21 | SOFTWARE. 22 | -------------------------------------------------------------------------------- /test-driven-dart.tex: -------------------------------------------------------------------------------- 1 | \documentclass[11pt,twoside=semi,openright,numbers=noenddot]{scrartcl} 2 | 3 | \input{tex/preamble.tex} 4 | 5 | \title{Test Driven Dart} 6 | \subtitle{\url{https://github.com/Yczar/test-driven-dart}} 7 | \author{} 8 | \date{Version: \tddversion} 9 | 10 | 11 | 12 | 13 | \begin{document} 14 | \baselineskip24pt 15 | \maketitle 16 | 17 | Welcome to Test Driven Dart! This repository is designed to guide Dart developers through the vast landscape of testing in Dart and Flutter, emphasizing a test-driven development (TDD) approach. 18 | 19 | \tableofcontents 20 | 21 | \newpage 22 | \input{tex/ch1-getting-started.tex} 23 | \newpage 24 | \input{tex/ch2-unit-tests.tex} 25 | \newpage 26 | \input{tex/ch3-widget-tests.tex} 27 | \newpage 28 | \input{tex/ch4-integration-tests.tex} 29 | \newpage 30 | \input{tex/ch5-test-tips-and-best-practices.tex} 31 | \newpage 32 | \input{tex/ch6-special-topics.tex} 33 | \newpage 34 | \input{tex/ch7-external-resources-and-links.tex} 35 | 36 | 37 | 38 | 39 | % Hello World! 40 | % \begin{code} 41 | % public class ClassName { 42 | % public static void main(String[] args) { 43 | % System.out.println(args); 44 | % } 45 | % } 46 | % \end{code} 47 | \end{document} -------------------------------------------------------------------------------- /script.sh: -------------------------------------------------------------------------------- 1 | #!/bin/sh 2 | 3 | pandoc -s --highlight-style=breezeDark --from markdown -o tdd.tex README.md \ 4 | 1_Getting_Started/1.1_Introduction_to_Testing.md \ 5 | 1_Getting_Started/1.2_Setting_Up_Testing_Environment.md \ 6 | 1_Getting_Started/1.3_Basic_Test_Structure.md \ 7 | 2_Unit_Tests/2.1_Basics_of_Unit_Testing.md \ 8 | 3_Widget_Tests/3.1_Introduction_to_Widget_Tests.md \ 9 | 3_Widget_Tests/3.2_Mocking_Widgets.md \ 10 | 3_Widget_Tests/3.3_Testing_Individual_Widgets.md \ 11 | 3_Widget_Tests/3.4_Advanced_Widget_Testing_Topics.md \ 12 | 4_Integration_Tests/4.1_Introduction_to_Integration_Tests.md \ 13 | 4_Integration_Tests/4.2_Setting_Up_Integration_Tests.md \ 14 | 4_Integration_Tests/4.3_Tips_for_Writing_Robust_Integration_Tests.md \ 15 | 5_Testing_Tips_and_Best_Practices/5.1_Organizing_Test_Code.md \ 16 | 5_Testing_Tips_and_Best_Practices/5.2_Continuous_Integration_and_Dart.md \ 17 | 5_Testing_Tips_and_Best_Practices/5.3_Common_Pitfalls_and_How_to_Avoid_Them.md \ 18 | 6_Special_Topics/6.1_TDD_in_Dart.md \ 19 | 6_Special_Topics/6.2_BDD_with_Dart.md \ 20 | 6_Special_Topics/6.3_Performance_Testing.md \ 21 | 7_External_Resources_and_Links/7.1_Official_Documentation_and_Guides.md \ 22 | 7_External_Resources_and_Links/7.2_Recommended_Books_and_Courses.md \ 23 | 7_External_Resources_and_Links/7.3_Related_Communities_and_Forums.md \ 24 | CONTRIBUTING.md -------------------------------------------------------------------------------- /1_Getting_Started/1.3_Basic_Test_Structure.md: -------------------------------------------------------------------------------- 1 | # Basic Test Structure in Dart 2 | 3 | Now that we've set up our testing environment, let's delve into the basic structure of a Dart test. Understanding this foundation will aid you as you explore more advanced testing topics. 4 | 5 | ## Anatomy of a Dart Test 6 | 7 | A typical Dart test file contains a series of `test` functions that each represent a single test case. Here's a simple breakdown: 8 | 9 | ### 1. Import the Test Package 10 | 11 | ```dart 12 | import 'package:test/test.dart'; 13 | ``` 14 | This imports the necessary functions and utilities to write tests. 15 | 16 | ### 2. Main Function 17 | Every Dart test file begins with a `main` function. It acts as an entry point for the test runner. 18 | ```dart 19 | void main() { 20 | // Your tests go here 21 | } 22 | ``` 23 | ### 3. The test Function 24 | The `test` function is where you define individual test cases. It takes two arguments: 25 | 26 | * A description of the test (String). 27 | * A callback function containing the test code. 28 | 29 | ```dart 30 | test('Description of the test', () { 31 | // Test code here 32 | }); 33 | ``` 34 | ### 4. Making Assertions with expect 35 | Within the test callback function, you use the `expect` function to assert that a value meets certain criteria. 36 | ```dart 37 | test('String splitting', () { 38 | var string = 'foo,bar,baz'; 39 | expect(string.split(','), equals(['foo', 'bar', 'baz'])); 40 | }); 41 | ``` 42 | In this example, `string.split(',')` is the actual value, and `equals(['foo', 'bar', 'baz'])` is the matcher that defines the expected value. 43 | 44 | ## Grouping Tests 45 | As your testing suite grows, organizing related tests into groups can be beneficial. Use the `group` function: 46 | ```dart 47 | group('String tests', () { 48 | test('String splitting', () { 49 | var string = 'foo,bar,baz'; 50 | expect(string.split(','), equals(['foo', 'bar', 'baz'])); 51 | }); 52 | 53 | // Other string-related tests 54 | }); 55 | ``` 56 | 57 | ## Conclusion 58 | The basic structure of a Dart test is both intuitive and expressive. As you progress in your Dart testing journey, you'll encounter more advanced utilities and functions to handle diverse scenarios. But the principles we covered in this section will always remain fundamental. 59 | 60 | Up next, we'll dive into unit testing in Dart, exploring how to test individual pieces of logic in isolation. 61 | 62 | Stay tuned! [Unit Tests](/2_Unit_Tests/2.1_Basics_of_Unit_Testing.md) 63 | -------------------------------------------------------------------------------- /CONTRIBUTING.md: -------------------------------------------------------------------------------- 1 | # Contributing to Test Driven Dart 2 | 3 | First and foremost, thank you! We appreciate that you want to contribute to **Test Driven Dart**. Your time and effort will help many Dart developers master the art of testing. 4 | 5 | ## Code of Conduct 6 | 7 | By participating in this project, you are expected to uphold our Code of Conduct. 8 | 9 | ## How to Contribute 10 | 11 | ### Reporting Bugs 12 | 13 | 1. Ensure the bug was not already reported by searching on GitHub under [Issues](https://github.com/YOUR_USERNAME/test-driven-dart/issues). 14 | 2. If you're unable to find an open issue addressing the problem, [open a new one](https://github.com/YOUR_USERNAME/test-driven-dart/issues/new). Be sure to include: 15 | - A title and clear description 16 | - As much relevant information as possible 17 | - A code sample or an executable test case demonstrating the expected behavior that is not occurring. 18 | 19 | ### Suggesting Enhancements 20 | 21 | 1. Check the [Issues](https://github.com/Yczar/test-driven-dart/issues) to see if there's already an enhancement suggestion that matches yours. 22 | 2. If not, create a new Issue with your suggestion. Be as clear and detailed as possible. 23 | 24 | ### Pull Requests 25 | 26 | 1. Fork the repository and create your branch from `master`. 27 | 2. Install the dependencies if you haven't already. 28 | 3. Make your changes ensuring they follow the existing code style and structure. 29 | 4. Run the tests to ensure no existing functionality is broken. 30 | 5. Add or update tests for your changes. 31 | 6. Commit your changes following a clear commit message pattern. 32 | 7. Push to your fork and submit a pull request to the `master` branch. 33 | 34 | ## Styleguides 35 | 36 | ### Git Commit Messages 37 | 38 | - Use the present tense ("Add feature" not "Added feature"). 39 | - Use the imperative mood ("Move cursor to..." not "Moves cursor to..."). 40 | - Limit the first line to 72 characters or less. 41 | - Reference issues and pull requests liberally after the first line. 42 | 43 | ### Dart Styleguide 44 | 45 | Follow the [official Dart style guide](https://dart.dev/guides/language/effective-dart/style). 46 | 47 | ## Additional Notes 48 | 49 | ### Issue and Pull Request Labels 50 | 51 | Label your issues or pull requests appropriately to help maintainers and other contributors understand your contribution's purpose and priority. 52 | 53 | ## Conclusion 54 | 55 | Your contributions are a valuable part of making this repository a comprehensive guide on Dart testing. By contributing, you're helping countless Dart developers improve their testing skills. 56 | -------------------------------------------------------------------------------- /7_External_Resources_and_Links/7.3_Related_Communities_and_Forums.md: -------------------------------------------------------------------------------- 1 | # Related Communities and Forums for Dart, Flutter, and Testing Enthusiasts 2 | Engaging with the community is one of the most effective ways to grow as a developer. By joining forums and online communities, you get the chance to share your knowledge, ask questions, learn from others' experiences, and stay updated with the latest trends and best practices. Below is a curated list of communities and forums related to Dart, Flutter, and testing. 3 | 4 | ## 1. Dart and Flutter Communities 5 | ### Reddit 6 | * [**r/dartlang**](https://www.reddit.com/r/dartlang/): Dedicated to the Dart language, its frameworks, and tools. 7 | * [**r/FlutterDev**](https://www.reddit.com/r/FlutterDev/): A bustling community of Flutter enthusiasts sharing projects, news, and tutorials. 8 | 9 | ### Stack Overflow 10 | * [**Dart Tag**](https://stackoverflow.com/questions/tagged/dart): A tag dedicated to Dart-related questions. 11 | * [**Flutter Tag**](https://stackoverflow.com/questions/tagged/flutter): A place where developers ask and answer questions about Flutter. 12 | 13 | ### Discord 14 | * [**Flutter Community**](https://discord.com/invite/N7Yshp4): An active server with discussions about all things Flutter. 15 | 16 | ## 2. Testing Communities 17 | ### Reddit 18 | * [**r/softwaretesting**](https://www.reddit.com/r/softwaretesting/): A community dedicated to software testing, methodologies, tools, and best practices. 19 | 20 | ### Stack Overflow 21 | * [**Unit Testing Tag**](https://stackoverflow.com/questions/tagged/unit-testing): Questions and discussions about unit testing across various languages, including Dart. 22 | 23 | ### Ministry of Testing 24 | [**Community**](https://www.ministryoftesting.com/): A massive community of testers with a plethora of resources, events, and forums dedicated to software testing. 25 | 26 | ## 3. General Tech and Developer Communities 27 | * [**Dev.to**](https://dev.to/): A platform where developers share articles, tutorials, and discussions. Search for `#dart` or `#flutter` to find related content. 28 | * [**Hashnode**](https://hashnode.com/): Another developer-centric platform with tons of Flutter and Dart content. 29 | 30 | ## 4. Local Meetups 31 | * [**Meetup.com**](https://www.meetup.com/): Search for local Dart and Flutter meetups in your city or region. These are great for networking and learning from local experts. 32 | 33 | ## Conclusion 34 | Communities and forums are a goldmine for knowledge and networking. They offer real-world insights, provide solutions to common problems, and most importantly, give a sense of belonging to a global family of developers and testers. 35 | 36 | 37 | 38 | -------------------------------------------------------------------------------- /1_Getting_Started/1.1_Introduction_to_Testing.md: -------------------------------------------------------------------------------- 1 | # Introduction to Testing in Dart 2 | 3 | Welcome to the introduction section of Test Driven Dart! Before we dive deep into various testing paradigms, let's establish a foundational understanding of why testing is critical, especially in a language as versatile as Dart. 4 | 5 | ## Why Testing Matters 6 | 7 | Testing is not just about ensuring the correctness of code – it's about assuring the quality of the end product, saving costs in the long term, and providing confidence when making changes. 8 | 9 | 1. **Code Quality Assurance**: Well-tested code tends to have fewer bugs, ensuring that the functionalities are working as expected. 10 | 2. **Long-term Savings**: Addressing bugs during development is cheaper than addressing them after the software is released. 11 | 3. **Confidence in Refactoring**: With comprehensive tests, developers can make changes without the fear of breaking existing functionalities. 12 | 4. **Documentation**: Tests provide an excellent documentation source, as they demonstrate how the code is supposed to work. 13 | 14 | ## Testing in Dart 15 | 16 | Dart, with its growing ecosystem and the backing of the Flutter framework, has seen a surge in its user base. This growth makes it even more important to establish robust testing practices. 17 | 18 | - **Rich Library Support**: Dart has built-in libraries, such as `package:test`, that provide tools to write unit tests, widget tests, and more. 19 | - **Flexibility**: Dart supports testing for both web and mobile applications, thanks to its versatile runtime. 20 | - **Integrated with Flutter**: For mobile developers using Flutter, Dart's testing capabilities are tightly integrated, allowing for widget testing and UI testing. 21 | 22 | ## Test Driven Development (TDD) 23 | 24 | Given our focus on "Test Driven Dart", it's essential to touch upon TDD briefly: 25 | 26 | TDD is a software development approach where tests are written before the actual code. The process follows a quick iteration of these three steps: 27 | 28 | 1. **Write a failing test**: Define what you expect a particular functionality to achieve but don't implement the functionality yet. 29 | 2. **Make the test pass**: Implement just enough code to make the test pass. 30 | 3. **Refactor**: Once the test is passing, optimize and clean up the code. 31 | 32 | In the upcoming sections, we'll dive deeper into TDD, exploring its benefits and seeing it in action with Dart. 33 | 34 | ## Conclusion 35 | 36 | Testing is a critical aspect of software development. With Dart, developers have a powerful and flexible platform to write and execute tests across various platforms. As we move forward in this guide, you'll learn the specifics of writing tests in Dart, emphasizing a test-driven approach. 37 | 38 | Up next, we'll be setting up our testing environment for Dart. Let's move on! [Next](./1.2_Setting_Up_Testing_Environment.md) 39 | 40 | 41 | -------------------------------------------------------------------------------- /1_Getting_Started/1.2_Setting_Up_Testing_Environment.md: -------------------------------------------------------------------------------- 1 | # Setting Up Testing Environment for Dart 2 | 3 | In this section, we'll walk you through setting up a testing environment for Dart applications. Having a well-configured environment is crucial for smooth test writing and execution. 4 | 5 | ## Prerequisites 6 | 7 | Before we begin, make sure you have: 8 | 9 | - Dart SDK installed. If not, you can download it from [Dart's official website](https://dart.dev/get-dart). 10 | - A code editor of your choice. While Dart is supported in many editors, [Visual Studio Code](https://code.visualstudio.com/) and [IntelliJ IDEA](https://www.jetbrains.com/idea/) are recommended due to their excellent Dart and Flutter plugin support. 11 | 12 | ## Step-by-Step Setup 13 | 14 | ### 1. Create a New Dart Project (Optional) 15 | 16 | If you're starting from scratch: 17 | 18 | ```bash 19 | dart create my_test_project 20 | cd my_test_project 21 | ``` 22 | This will generate a new Dart project in a directory named my_test_project. 23 | 24 | ### 2. Adding the Test Package 25 | 26 | Add the test package to your pubspec.yaml under dev_dependencies: 27 | ```yaml 28 | dev_dependencies: 29 | test: ^any_version 30 | ``` 31 | Run `dart pub get` to install the new dependency. 32 | 33 | ### 3. Creating a Test Directory 34 | 35 | By convention, Dart applications have a `test` directory at the root level for all test files. If it doesn't exist, create it: 36 | ```bash 37 | mkdir test 38 | ``` 39 | 40 | ### 4. Writing Your First Test 41 | Inside the test directory, create a new file named `sample_test.dart` and add the following content: 42 | ```dart 43 | import 'package:test/test.dart'; 44 | 45 | void main() { 46 | test('String split', () { 47 | var string = 'foo,bar,baz'; 48 | expect(string.split(','), equals(['foo', 'bar', 'baz'])); 49 | }); 50 | } 51 | ``` 52 | 53 | ### 5. Running the Test 54 | Navigate to the root directory of your project in the terminal and run: 55 | 56 | ```bash 57 | dart test 58 | ``` 59 | 60 | This will execute all tests in the test directory. You should see a message indicating that the test passed. 61 | 62 | ### Tips for a Smooth Testing Experience 63 | * Organize your Tests: As your project grows, consider organizing tests in folders within the test directory based on functionalities or modules. 64 | * Use Descriptive Test Names: Always name your tests descriptively to make it easy for other developers (or future you) to understand the purpose of each test. 65 | * Continuous Integration (CI): Consider setting up a CI pipeline to automatically run tests whenever you push code changes. 66 | 67 | ### Conclusion 68 | Setting up a testing environment for Dart is straightforward, thanks to its well-designed tools and packages. Now that you've laid down the groundwork, you're ready to dive deeper into the world of Dart testing. 69 | 70 | In the next section, we'll explore the basic structure of a Dart test. [Onward!](./1.3_Basic_Test_Structure.md) 71 | 72 | 73 | -------------------------------------------------------------------------------- /4_Integration_Tests/4.1_Introduction_to_Integration_Tests.md: -------------------------------------------------------------------------------- 1 | # Introduction to Integration Tests in Flutter 2 | While unit and widget tests are critical for ensuring the correctness of individual pieces of your application, integration tests focus on testing larger chunks or the entire application itself. This ensures that all parts work together harmoniously, yielding the desired overall behavior. 3 | 4 | ## What are Integration Tests? 5 | Integration tests in Flutter are tests that ensure that multiple parts of your app work together correctly. They often: 6 | 7 | 1. Run the entire app. 8 | 2. Simulate user behavior (like tapping, scrolling, and keying in text). 9 | 3. Ensure that these interactions yield the desired results. 10 | 11 | ## Why Integration Testing? 12 | ### 1. Holistic Application Behavior: 13 | Ensure that the entire system behaves as expected when different pieces come together. 14 | 15 | ### 2. User Flow Verification: 16 | Check if the overall user experience is smooth and the app behaves correctly through user scenarios or stories. 17 | 18 | ### 3. Detecting Regression: 19 | Identify any unintentional side effects that might arise when making changes in the codebase. 20 | 21 | ### Setting Up 22 | To start with integration testing in Flutter, you'll need the `integration_test` package. 23 | ```yaml 24 | dev_dependencies: 25 | integration_test: 26 | sdk: flutter 27 | ``` 28 | ### Writing Your First Integration Test 29 | Integration tests reside in the `integration_test` folder and often use both the `test` and `flutter_test` libraries. 30 | 31 | Example structure: 32 | ```dart 33 | import 'package:integration_test/integration_test.dart'; 34 | import 'package:flutter_test/flutter_test.dart'; 35 | import 'package:my_app/main.dart'; 36 | 37 | void main() { 38 | IntegrationTestWidgetsFlutterBinding.ensureInitialized(); 39 | 40 | group('Main App Flow', () { 41 | testWidgets('Navigating through the app', (tester) async { 42 | // Start the app 43 | await tester.pumpWidget(MyApp()); 44 | 45 | // Interact with the app 46 | await tester.tap(find.text('Next')); 47 | await tester.pumpAndSettle(); 48 | 49 | // Assertions 50 | expect(find.text('Page 2'), findsOneWidget); 51 | }); 52 | }); 53 | } 54 | ``` 55 | 56 | ### Running Integration Tests 57 | Integration tests can be run on both real devices and emulators. Use the following command: 58 | ```bash 59 | flutter test integration_test/my_test.dart 60 | ``` 61 | For more advanced scenarios, you might want to look into the `flutter drive` command. 62 | 63 | ### Conclusion 64 | Integration tests are a vital part of ensuring that your app works as a cohesive unit. While they might take longer to run than unit or widget tests, they offer assurance that your app works correctly from the user's perspective. 65 | 66 | In subsequent chapters, we'll delve deeper into advanced integration testing topics, automation, and best practices to get the most out of your testing efforts. [Next](/4_Integration_Tests/4.2_Setting_Up_Integration_Tests.md) 67 | -------------------------------------------------------------------------------- /7_External_Resources_and_Links/7.2_Recommended_Books_and_Courses.md: -------------------------------------------------------------------------------- 1 | # Recommended Books and Courses on Dart, Flutter, and Testing 2 | There's a plethora of learning resources available, spanning various formats. Books offer in-depth knowledge, while online courses provide an interactive experience with potential hands-on exercises. This section curates a list of notable books and courses tailored for Dart, Flutter, and software testing enthusiasts. 3 | 4 | ## 1. Books on Dart and Flutter 5 | ### Dart 6 | **"Dart: Up and Running"** by Kathy Walrath and Seth Ladd 7 | 8 | * An introductory guide to Dart, covering the basics and diving into more advanced topics. 9 | 10 | **"Dart for Absolute Beginners"** by David Kopec 11 | 12 | * A beginner-friendly approach to Dart programming, perfect for those new to the language. 13 | 14 | ## Flutter 15 | 1. **"Flutter in Action"** by Eric Windmill 16 | 17 | * Comprehensive coverage of Flutter, from setting up to building complex apps. 18 | 19 | 2. **"Beginning Flutter: A Hands-On Guide to App Development"** by Marco L. Napoli 20 | 21 | * Step-by-step guide to building Flutter applications, ideal for beginners. 22 | 23 | ## 2. Books on Software Testing 24 | 1. **"Clean Code: A Handbook of Agile Software Craftsmanship"** by Robert C. Martin 25 | 26 | * While not exclusively on testing, it covers writing maintainable and testable code. 27 | 28 | 2. **"Test Driven Development: By Example"** by Kent Beck 29 | 30 | * A classic read on the TDD methodology and its practical implementation. 31 | 32 | 3. **"Pragmatic Unit Testing in Java with JUnit"** by Andy Hunt and Dave Thomas 33 | 34 | * Offers insights into unit testing which can be extrapolated to Dart and Flutter environments. 35 | 36 | ## 3. Courses on Dart and Flutter Testing 37 | 1. **"Dart and Flutter: The Complete Developer's Guide"** on Udemy by Stephen Grider 38 | 39 | * Comprehensive coverage of Dart and Flutter, with dedicated sections on testing. 40 | 2. **"Flutter Testing Masterclass"** on Udacity 41 | 42 | * A deep dive into Flutter testing methodologies, from unit to integration testing. 43 | 3. **"Mastering Dart Testing"** on Pluralsight 44 | 45 | * Focuses on advanced testing techniques, patterns, and best practices in Dart. 46 | 47 | ## 4. Additional Learning Resources 48 | **"Software Testing Tutorial"** on Coursera 49 | 50 | * A broader perspective on software testing, with methodologies that can be applied to Dart and Flutter. 51 | 52 | **"Advanced Flutter Architectures"** on Udemy 53 | 54 | * Focuses on building scalable and testable Flutter applications, emphasizing best practices. 55 | 56 | ## Conclusion 57 | Books and courses provide structured paths to mastery. While the official documentation remains a vital resource, these curated materials offer additional perspectives, examples, and methodologies. As always, it's crucial to practice as you learn, implementing the concepts in real-world projects to solidify your understanding. [Next](/7_External_Resources_and_Links/7.3_Related_Communities_and_Forums.md) 58 | 59 | -------------------------------------------------------------------------------- /2_Unit_Tests/2.1_Basics_of_Unit_Testing.md: -------------------------------------------------------------------------------- 1 | # Basics of Unit Testing in Dart 2 | Unit testing focuses on verifying the correctness of individual units of source code, such as functions or methods, in isolation from the rest of the application. In this section, we'll break down the fundamental concepts and practices of unit testing in Dart. 3 | 4 | # What is a "Unit"? 5 | In the context of testing, a "unit" refers to the smallest testable part of any software. It can be an entire module or just a single function. The primary goal is to validate that each unit of the software code performs as expected. 6 | 7 | # Why Unit Testing? 8 | 1. **Quick Feedback**: Unit tests are generally fast and can be run frequently, providing immediate feedback to developers. 9 | 2. **Improved Design**: Writing tests often leads to better code design and modularity. 10 | 3. **Easier Refactoring**: Tests ensure that refactoring doesn't introduce regressions. 11 | 4. **Documentation**: Tests can serve as documentation, showcasing how a piece of code is expected to behave. 12 | 13 | # Writing a Unit Test in Dart 14 | ## 1. Choose the Unit to Test 15 | Decide on a function or method that you want to test. For this example, let's consider a simple function that returns the sum of two numbers: 16 | ```dart 17 | int sum(int a, int b) { 18 | return a + b; 19 | } 20 | ``` 21 | 22 | ## 2. Decide on Test Cases 23 | Think about the different inputs this function can have and what the expected outputs are. For our sum function: 24 | 25 | * sum(3, 4) should return 7. 26 | * sum(-3, 4) should return 1. 27 | 28 | ## 3. Write the Test 29 | ```dart 30 | import 'package:test/test.dart'; 31 | import 'path_to_your_function.dart'; // Adjust this import path 32 | 33 | void main() { 34 | test('Positive numbers', () { 35 | expect(sum(3, 4), 7); 36 | }); 37 | 38 | test('Mix of negative and positive numbers', () { 39 | expect(sum(-3, 4), 1); 40 | }); 41 | } 42 | ``` 43 | Run the tests using `dart test` in your terminal. 44 | 45 | # Mocking in Unit Tests 46 | Often, you'll want to test units that have external dependencies like databases or APIs. In unit tests, these dependencies should be isolated using "mocks". Dart's `mockito` package is an excellent tool for this purpose, which we will delve into in a subsequent section. 47 | 48 | # Best Practices 49 | 1. **One Assertion per Test**: Ideally, each test should verify just one behavior. 50 | 2. **Descriptive Test Names**: Your test descriptions should explain what the test does, e.g., 'Calculating sum of two positive numbers'. 51 | 3. **Test Edge Cases**: Apart from the usual cases, test boundary and unexpected input cases. 52 | 4. **Keep Tests Independent**: One test should not depend on another. Each test should be standalone. 53 | 54 | # Conclusion 55 | Unit tests form the backbone of any software testing strategy. They're vital for ensuring the correctness of individual units of code and building robust applications. In upcoming sections, we'll explore advanced unit testing techniques, patterns, and tools that are pivotal in Dart. [Next](/3_Widget_Tests/3.1_Introduction_to_Widget_Tests.md) 56 | -------------------------------------------------------------------------------- /6_Special_Topics/6.2_BDD_with_Dart.md: -------------------------------------------------------------------------------- 1 | # Behavior-Driven Development (BDD) in Dart 2 | Behavior-Driven Development (BDD) extends the principles of Test-Driven Development (TDD) by emphasizing collaboration between developers, QA, and non-technical participants. It focuses on defining the expected behavior of a system from the user's perspective. Let's delve into the concept of BDD within Dart and Flutter applications. 3 | 4 | ## 1. What is BDD? 5 | BDD bridges the gap between technical and non-technical stakeholders by using plain language specifications to describe software behavior. These specifications are then translated into tests. 6 | 7 | ## 2. Advantages of BDD 8 | * **Clearer Understanding**: Requirements are better understood since everyone is involved. 9 | * **Reduced Ambiguity**: Plain language specifications reduce misunderstandings. 10 | * **Focus on User Value**: Features are designed around user needs. 11 | * **Living Documentation**: BDD specs act as up-to-date documentation. 12 | 13 | ## 3. BDD in Dart with Gherkin 14 | `flutter_gherkin` is a popular tool for BDD, and there's a Dart implementation named `gherkin` that allows writing BDD-style tests in Dart. 15 | 16 | Example BDD Workflow: 17 | 1. **Define a Feature** 18 | 19 | In a `.feature` file, describe the behavior: 20 | ```vbnet 21 | Feature: Square a number 22 | As a mathematician 23 | I want to square numbers 24 | So that I can obtain the product of a number with itself. 25 | ``` 26 | 2. **Write Scenarios** 27 | 28 | Scenarios outline specific instances of the feature: 29 | ```mathematica 30 | Scenario: Squaring a positive number 31 | Given I have the number 5 32 | When I square the number 33 | Then I should get 25 34 | ``` 35 | 36 | 3. **Implement Step Definitions** 37 | 38 | Now, using Dart and gherkin, implement the steps: 39 | ```dart 40 | Given('I have the number {int}', (int number) async { 41 | // Store the number for the next steps. 42 | }); 43 | 44 | When('I square the number', () async { 45 | // Square the number. 46 | }); 47 | 48 | Then('I should get {int}', (int expected) async { 49 | // Assert the squared result. 50 | }); 51 | ``` 52 | 4. **BDD and Flutter** 53 | 54 | For Flutter, BDD can help in defining UI/UX behavior and interactions. You can use packages like flutter_gherkin to implement BDD-style tests for Flutter applications. 55 | 56 | 1. Define the feature and scenarios in `.feature` files. 57 | 2. Write step definitions using Flutter's testing framework to interact with widgets and verify behavior. 58 | 59 | 5. **Challenges and Considerations:** 60 | 61 | * **Learning Curve**: Understanding and setting up BDD tools can take time. 62 | * **Maintaining Specs**: As with any test, keeping BDD specs up-to-date is crucial. 63 | * **Avoid Over-Specification:** Focus on key behaviors and avoid writing specs for trivial features. 64 | 65 | ## Conclusion 66 | BDD is a powerful approach, especially for projects where clear communication between stakeholders is critical. By focusing on user behavior, Dart and Flutter developers can create more user-centric applications. [Next](/6_Special_Topics/6.3_Performance_Testing.md) 67 | -------------------------------------------------------------------------------- /6_Special_Topics/6.1_TDD_in_Dart.md: -------------------------------------------------------------------------------- 1 | # Test-Driven Development (TDD) in Dart 2 | Test-Driven Development (TDD) is a software development methodology where tests are written before the actual code, leading to cleaner, more maintainable, and bug-resistant code. Here, we'll discuss the ins and outs of TDD in Dart development. 3 | 4 | ## 1. Introduction to TDD 5 | TDD revolves around a short and iterative development cycle. The developer: 6 | 7 | 1. Writes a failing test. 8 | 2. Writes the minimal code to make the test pass. 9 | 3. Refactors the code for optimization and clarity, ensuring tests still pass. 10 | 11 | ## 2. Benefits of TDD 12 | * **Higher Code Quality**: Catch issues early in development. 13 | * **Improved Design**: Code evolves organically, leading to better architecture. 14 | * **Confidence**: Changes can be made without fearing unintended consequences. 15 | * **Documentation**: Tests act as a documentation source, showing how a system should behave. 16 | 17 | ## 3. TDD Cycle in Dart 18 | ### 1. Write a Failing Test 19 | Start by thinking about what the function or feature should do and then write a test for that. 20 | ```dart 21 | void main() { 22 | test('should return the square of a number', () { 23 | final result = square(5); 24 | expect(result, equals(25)); 25 | }); 26 | } 27 | ``` 28 | This test will fail because we haven't defined the `square` function yet. 29 | 30 | ### 2. Implement the Functionality 31 | Write just enough code to make the test pass: 32 | ```dart 33 | int square(int number) { 34 | return number * number; 35 | } 36 | ``` 37 | 38 | ### 3. Refactor 39 | If you see any opportunity to improve the code without altering its behavior, do it now: 40 | ```dart 41 | int square(int number) => number * number; 42 | ``` 43 | ## 4. Common TDD Practices in Dart 44 | * **Mocking**: Use Dart's mockito package to mock dependencies and focus on testing the unit at hand. 45 | * **Red-Green-Refactor**: Remember the TDD cycle – first the test fails (Red), then make it pass (Green), and finally refactor. 46 | * **Continuous Integration**: Run tests on every code change using CI tools to ensure no regression. 47 | 48 | ## 5. Challenges in TDD 49 | * **Initial Overhead**: TDD can feel slower at the start. 50 | * **Learning Curve**: It requires a shift in mindset from traditional coding. 51 | * **Over-reliance** : Not every tiny piece of code needs to be driven by tests. Balance is key. 52 | 53 | ## 6. TDD with Flutter 54 | In Flutter, TDD can be employed to create widget tests and integration tests: 55 | 56 | 1. Create a widget test to verify a certain UI state or behavior. 57 | 2. Build the widget to satisfy the test. 58 | 3. Refactor if needed, ensuring the test remains green. 59 | 60 | ## Conclusion 61 | TDD is a powerful methodology that can significantly elevate the quality of your Dart and Flutter applications. While it requires a bit of initial investment and a change in mindset, the benefits in terms of code reliability, maintainability, and overall quality are immense. 62 | 63 | In the subsequent sections, we'll dive deeper into practical TDD scenarios, explore tools that can aid TDD in Dart, and investigate advanced TDD strategies for scalable applications. [Next](/6_Special_Topics/6.2_BDD_with_Dart.md) 64 | -------------------------------------------------------------------------------- /7_External_Resources_and_Links/7.1_Official_Documentation_and_Guides.md: -------------------------------------------------------------------------------- 1 | # Official Documentation and Guides for Dart and Flutter Testing 2 | Understanding and leveraging official documentation is key to becoming proficient in any framework or language. Dart and Flutter have comprehensive official guides and API references that are invaluable to developers. In this section, we'll provide an overview and curated list of these resources. 3 | 4 | ## 1. Why Use Official Documentation? 5 | * **Accuracy**: Content is maintained by experts and typically undergoes rigorous review. 6 | * **Up-to-date**: As Dart and Flutter evolve, so does the documentation, ensuring relevance. 7 | * **Comprehensiveness**: Covers everything from basic topics to advanced techniques. 8 | * **Examples**: Contains practical, executable examples that help solidify understanding. 9 | 10 | ## 2. Dart Testing 11 | ### Dart Test Package 12 | Dart provides a unit testing framework via the `[test](https://pub.dev/packages/test)` package. 13 | 14 | * [**Getting Started**](https://pub.dev/packages/test#-readme-tab-): Introduction to setting up and writing basic tests. 15 | * [**Configuration**](https://github.com/dart-lang/test/blob/master/pkgs/test/doc/configuration.md): Dive deep into configuring test suites for various needs. 16 | 17 | ### Mocking in Dart 18 | Using the `[mockito](https://pub.dev/packages/mockito)` package, simulate the behavior of real objects in controlled ways. 19 | * [**Mockito Basics**](https://pub.dev/packages/mockito): Learn how to create and use mock objects. 20 | 21 | ## 3. Flutter Testing 22 | Flutter provides a rich set of testing utilities that cater to different layers, from widget testing to integration testing. 23 | 24 | Flutter Test Package 25 | The foundational package for all testing activities in Flutter. 26 | 27 | * [**Introduction to Testing**](https://docs.flutter.dev/testing): A broad overview of testing in Flutter. 28 | * [**Unit Testing with Flutter**](https://docs.flutter.dev/cookbook/testing/unit/introduction): Guidelines for writing unit tests. 29 | * [**Widget Testing**](https://docs.flutter.dev/cookbook/testing/widget/introduction): Dive into the nuances of testing Flutter widgets. 30 | * [**Integration Testing**](https://docs.flutter.dev/cookbook/testing/integration/introduction): Understand testing complete flows or interactions. 31 | 32 | ## Flutter Performance Testing 33 | Understanding and monitoring the performance of your Flutter apps is essential. 34 | 35 | * [**Performance Profiling**](https://flutter.dev/docs/testing/ui-performance): Tools and tips for profiling app performance. 36 | 37 | ## 4. Additional Resources 38 | [**Effective Dart**](https://dart.dev/effective-dart): Best practices for coding, designing, and testing Dart code. 39 | [**Flutter Samples**](https://github.com/flutter/samples): A GitHub repository filled with Flutter samples, including various testing examples. 40 | 41 | ## Conclusion 42 | Embracing the wealth of official documentation and guides is a surefire way to enhance your Dart and Flutter testing skills. While other resources, tutorials, and community contributions are valuable, the official docs act as a cornerstone for understanding and best practices. [Next](/7_External_Resources_and_Links/7.2_Recommended_Books_and_Courses.md) 43 | -------------------------------------------------------------------------------- /4_Integration_Tests/4.2_Setting_Up_Integration_Tests.md: -------------------------------------------------------------------------------- 1 | # Setting Up Integration Tests in Flutter 2 | Integration tests provide a comprehensive approach to verifying the correct functioning of your Flutter applications from a holistic perspective. Before writing and running these tests, though, you need to set them up correctly. This guide will walk you through the setup process step-by-step. 3 | 4 | ## Step 1: Dependencies 5 | First, you'll need to add the necessary dependencies to your `pubspec.yaml`: 6 | ```yaml 7 | dev_dependencies: 8 | integration_test: 9 | sdk: flutter 10 | flutter_test: 11 | sdk: flutter 12 | ``` 13 | Run `flutter pub get` to fetch the required packages. 14 | 15 | ## Step 2: Directory Structure 16 | It's a good practice to organize your integration tests in a separate directory to keep them distinct from unit and widget tests. Create an `integration_test` directory at the root level of your project. 17 | ```lua 18 | my_app/ 19 | |-- lib/ 20 | |-- test/ 21 | |-- integration_test/ 22 | | |-- app_test.dart 23 | |-- pubspec.yaml 24 | ``` 25 | 26 | ## Step 3: Configuration 27 | Start by importing the necessary libraries and initializing the integration test widgets binding. This ensures your tests have the resources they need to execute correctly. 28 | 29 | `app_test.dart:` 30 | ```dart 31 | import 'package:integration_test/integration_test.dart'; 32 | import 'package:flutter_test/flutter_test.dart'; 33 | import 'package:my_app/main.dart'; 34 | 35 | void main() { 36 | IntegrationTestWidgetsFlutterBinding.ensureInitialized(); 37 | 38 | // Your integration tests go here... 39 | } 40 | ``` 41 | 42 | ## Step 4: Writing a Basic Test 43 | Within your `main` function, you can begin defining tests. Here's a simple example where we launch the app and check if the homepage is displayed: 44 | 45 | ```dart 46 | testWidgets('Homepage displays correctly', (tester) async { 47 | await tester.pumpWidget(MyApp()); 48 | 49 | // Check if homepage title exists 50 | expect(find.text('Homepage'), findsOneWidget); 51 | }); 52 | ``` 53 | 54 | ## Step 5: Running the Tests 55 | To execute integration tests, use the `flutter test` command, specifying the path to your integration test file: 56 | ```bash 57 | flutter test integration_test/app_test.dart 58 | ``` 59 | For more complex scenarios involving multiple devices, you might use the `flutter drive` command. 60 | 61 | ## Step 6: Continuous Integration (Optional) 62 | For larger projects, you may wish to automate your integration tests using a Continuous Integration (CI) platform like GitHub Actions, Travis CI, or CircleCI. This will automatically run your tests on every commit, ensuring constant feedback and early bug detection. 63 | 64 | ## Conclusion 65 | Setting up integration tests in Flutter might seem like a few extra steps in the beginning, but the confidence these tests provide in ensuring your app's overall behavior is invaluable. As your app grows, these tests will serve as a safety net, helping catch issues that unit or widget tests might miss. 66 | 67 | In the upcoming sections, we'll delve deeper into writing complex integration tests, simulating user interactions, and best practices to ensure you extract maximum value from your tests. [Next](/4_Integration_Tests/4.3_Tips_for_Writing_Robust_Integration_Tests.md) 68 | 69 | 70 | -------------------------------------------------------------------------------- /4_Integration_Tests/4.3_Tips_for_Writing_Robust_Integration_Tests.md: -------------------------------------------------------------------------------- 1 | # Tips for Writing Robust Integration Tests in Flutter 2 | Writing integration tests is one thing; ensuring they're robust, maintainable, and effective is another. This guide offers tips and best practices to bolster the resilience and usefulness of your integration tests in Flutter. 3 | 4 | ## 1. Use Descriptive Test Names 5 | Clear test names make it easier to identify the test purpose and debug if they fail. 6 | ```dart 7 | testWidgets('Should navigate to user profile when tapping avatar', (tester) async { ... }); 8 | ``` 9 | 10 | ## 2. Utilize Keys 11 | Assign `Key` values to your widgets, especially when they're dynamically generated. It makes them easier to locate during testing. 12 | ```dart 13 | ListView.builder( 14 | itemBuilder: (context, index) => ListTile(key: ValueKey('item_$index'), ...), 15 | ); 16 | ``` 17 | In tests: 18 | ```dart 19 | await tester.tap(find.byKey(ValueKey('item_2'))); 20 | ``` 21 | 22 | ## 3. Avoid Magic Numbers 23 | Use named constants to define timeouts, index values, or any other numbers in tests. 24 | ```dart 25 | const defaultTimeout = Duration(seconds: 10); 26 | ``` 27 | 28 | ## 4. Opt for pumpAndSettle Wisely 29 | While `pumpAndSettle` can be useful, it might lead to flakiness or longer test run times. Sometimes, it's better to use `pump` with specific durations. 30 | 31 | ## 5. Check Multiple States 32 | Beyond checking the final state, ensure intermediate states in a flow are as expected. This can help catch issues where the final state is correct, but the journey there isn't. 33 | 34 | ## 6. Limit External Dependencies 35 | If your integration tests rely heavily on external services or databases, they can become slow or flaky. Mock these services or use test doubles when possible. 36 | 37 | ## 7. Run on Different Devices and Orientations 38 | Differences in screen sizes, resolutions, or orientations can cause unexpected behavior. Consider running tests on various emulators and real devices. 39 | 40 | ## 8. Group Related Tests 41 | Utilize `group` to bundle related tests together. This aids in readability and organization. 42 | ```dart 43 | group('User Profile Tests', () { 44 | testWidgets('Displays user info', ...); 45 | testWidgets('Updates on edit', ...); 46 | }); 47 | ``` 48 | ## 9. Refrain from Over-Testing 49 | Avoid writing integration tests for every possible scenario, especially if it's already covered by unit or widget tests. Focus on critical user journeys. 50 | 51 | ## 10. Stay Updated 52 | Flutter is rapidly evolving, and new testing functionalities or best practices may emerge. Regularly check Flutter's official documentation and the broader community's insights. 53 | 54 | ## Conclusion 55 | Crafting robust integration tests is a mix of understanding your application's architecture, predicting user behavior, and adopting good testing practices. With the tips mentioned above, you'll be well-equipped to write resilient tests that offer meaningful feedback and ensure your application's reliability from a holistic standpoint. 56 | 57 | In the coming chapters, we'll explore more advanced integration testing scenarios, dive deeper into automation, and examine techniques for enhancing your test suite's efficiency. [Next](/5_Testing_Tips_and_Best_Practices/5.1_Organizing_Test_Code.md) 58 | -------------------------------------------------------------------------------- /3_Widget_Tests/3.1_Introduction_to_Widget_Tests.md: -------------------------------------------------------------------------------- 1 | # Introduction to Widget Tests in Flutter 2 | While unit tests verify the correctness of individual units of code, widget tests (also known as component tests) assess individual widgets in isolation. Given that widgets are the central building blocks of Flutter applications, ensuring their correct behavior and rendering is essential. In this section, we will introduce the basics of widget testing in Flutter. 3 | 4 | # What are Widget Tests? 5 | In Flutter, everything from a button to a screen is a widget. Widget tests ensure that each of these widgets behaves and appears as expected when interacted with. Instead of running the full app, widget tests focus on a single widget, making them more efficient than full app tests but more comprehensive than unit tests. 6 | 7 | # Setting Up 8 | To write widget tests, you need the `flutter_test` package, which is typically included in the `dev_dependencies` section of your `pubspec.yaml` file: 9 | ```yaml 10 | dev_dependencies: 11 | flutter_test: 12 | sdk: flutter 13 | ``` 14 | # Writing a Basic Widget Test 15 | 16 | ## 1. Import Necessary Libraries 17 | At the beginning of your test file: 18 | ```dart 19 | import 'package:flutter_test/flutter_test.dart'; 20 | import 'package:your_app/path_to_your_widget.dart'; 21 | ``` 22 | 23 | ## 2. Write the Test 24 | Widget tests use the testWidgets function. Here's an example of testing a simple RaisedButton: 25 | ```dart 26 | void main() { 27 | testWidgets('Renders a raised button', (WidgetTester tester) async { 28 | // Build our app and trigger a frame. 29 | await tester.pumpWidget(MaterialApp(home:RaisedButton(onPressed: () {}, child: Text('Click me')))); 30 | 31 | // Verify if the button is displayed. 32 | expect(find.byType(RaisedButton), findsOneWidget); 33 | expect(find.text('Click me'), findsOneWidget); 34 | }); 35 | } 36 | ``` 37 | ## 3. Run the Test 38 | Use the command: 39 | ```bash 40 | flutter test path_to_your_test_file.dart 41 | ``` 42 | 43 | # Interacting with Widgets in Tests 44 | `WidgetTester` provides a multitude of methods to simulate interactions: 45 | 46 | * **Tap**: `tester.tap(find.byType(RaisedButton));` 47 | * **Drag**: `tester.drag(find.byType(ListView), Offset(0, -200));` 48 | * **Enter Text**: `tester.enterText(find.byType(TextField), 'Hello Flutter')`; 49 | After any interaction, you typically call `tester.pump()` to rebuild the widget tree and reflect changes. 50 | 51 | # Benefits of Widget Tests 52 | 1. **Confidence**: Ensure that changes or refactors don't break your UI. 53 | 2. **Speed**: Faster than full app integration tests since they don't involve the entire system. 54 | 3. **Documentation**: They serve as documentation, showcasing how a widget is expected to behave and look. 55 | 56 | # Conclusion 57 | Widget tests are an invaluable tool in the Flutter developer's toolkit. They bridge the gap between unit tests and full app integration tests, offering a middle ground that validates the UI's correctness without the overhead of running the entire app. 58 | 59 | As you delve deeper into Flutter development, harnessing the power of widget tests will be crucial in building robust, bug-free apps. 60 | 61 | In the next sections, we'll explore advanced techniques and best practices in widget testing. 62 | 63 | Stay tuned! [Next](/3_Widget_Tests/3.2_Mocking_Widgets.md) 64 | -------------------------------------------------------------------------------- /5_Testing_Tips_and_Best_Practices/5.3_Common_Pitfalls_and_How_to_Avoid_Them.md: -------------------------------------------------------------------------------- 1 | # Common Testing Pitfalls in Dart and Flutter and How to Avoid Them 2 | While testing is an integral part of the software development process, it's not immune to challenges and pitfalls. Here, we'll outline some common mistakes developers might encounter and provide solutions to avoid them. 3 | 4 | ## 1. Flaky Tests 5 | ### Pitfall: 6 | Tests intermittently pass or fail without any apparent changes to the code. 7 | 8 | ### Solution: 9 | * Ensure there's no dependency on external factors like time, random number generation, or network. 10 | * Avoid using `pumpAndSettle` indiscriminately in widget tests. 11 | * Check if asynchronous code is correctly handled in tests. 12 | 13 | ## 2. Overmocking 14 | ### Pitfall: 15 | Replacing too many real implementations with mocks, making tests pass even when the real implementation is broken. 16 | 17 | ### Solution: 18 | * Mock only the parts that are absolutely necessary, like external services. 19 | * Occasionally run tests with real implementations to verify their accuracy. 20 | 21 | ## 3. Testing Implementation Instead of Behavior 22 | ### Pitfall: 23 | Writing tests that are overly tied to the implementation details, causing them to break when refactoring. 24 | 25 | ### Solution: 26 | * Write tests based on the expected behavior or outcome. 27 | * Avoid relying on internal state unless it's directly related to the test's objective. 28 | 29 | ## 4. Not Testing Edge Cases 30 | ### Pitfall: 31 | Only testing the "happy path" and neglecting potential edge cases or error scenarios. 32 | 33 | ### Solution: 34 | * Identify potential edge cases through brainstorming or tools. 35 | * Use techniques like boundary value analysis or decision tables. 36 | 37 | ## 5. Ignoring Test Failures 38 | ### Pitfall: 39 | Over time, a few failing tests are ignored, assuming they aren't important. 40 | 41 | ### Solution: 42 | * Treat every test failure as a potential issue. 43 | * If a test is consistently failing without reason, consider revisiting its logic. 44 | 45 | ## 6. Large and Complicated Test Setups 46 | ### Pitfall: 47 | Setting up a complex environment for each test, making it hard to understand and maintain. 48 | 49 | ### Solution: 50 | * Use setUp and tearDown for common setups and clean-ups. 51 | * Break down complex setups into smaller, reusable functions. 52 | 53 | ## 7. Not Using Continuous Integration 54 | ### Pitfall: 55 | Not getting feedback on tests from an environment similar to production. 56 | 57 | ### Solution: 58 | * Integrate a CI system to run tests automatically on every code change. 59 | * Ensure the CI environment mirrors the production environment as closely as possible. 60 | 61 | ## 8. Lack of Test Documentation 62 | ### Pitfall: 63 | Other developers struggle to understand the purpose or context of tests. 64 | 65 | ### Solution: 66 | * Use clear and descriptive test names. 67 | * Comment complex or non-intuitive parts of test code. 68 | 69 | ## Conclusion 70 | Every developer, regardless of experience, can fall into the trap of these pitfalls. Recognizing and addressing them early ensures that your test suite remains a valuable asset rather than becoming a liability. With the insights shared above, you'll be better equipped to create and maintain effective, reliable tests for your Dart and Flutter projects. [Next](/6_Special_Topics/6.1_TDD_in_Dart.md) 71 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # Test Driven Dart 2 | 3 | [![CI](https://github.com/Yczar/test-driven-dart/actions/workflows/build.yml/badge.svg?event=push)](https://github.com/Yczar/test-driven-dart/actions/workflows/build.yml) 4 | 5 | Welcome to Test Driven Dart! This repository is designed to guide Dart developers through the vast landscape of testing in Dart and Flutter, emphasizing a test-driven development (TDD) approach. 6 | 7 | ## Table of Contents 8 | 9 | - [Getting Started](./1_Getting_Started/1.1_Introduction_to_Testing.md) 10 | - [Introduction to Testing](./1_Getting_Started/1.1_Introduction_to_Testing.md) 11 | - [Setting Up Testing Environment](./1_Getting_Started/1.2_Setting_Up_Testing_Environment.md) 12 | - [Basic Test Structure](./1_Getting_Started/1.3_Basic_Test_Structure.md) 13 | - [Unit Tests](./2_Unit_Tests/2.1_Basics_of_Unit_Testing.md) 14 | - [Basics of Unit Testing](./2_Unit_Tests/2.1_Basics_of_Unit_Testing.md) 15 | - [Mocking in Dart](./2_Unit_Tests/2.2_Mocking_in_Dart.md) 16 | - [Testing Classes and Functions](./2_Unit_Tests/2.3_Testing_Classes_and_Functions.md) 17 | - [Widget Tests](./3_Widget_Tests/3.1_Introduction_to_Widget_Tests.md) 18 | - [Introduction to Widget Tests](./3_Widget_Tests/3.1_Introduction_to_Widget_Tests.md) 19 | - [Mocking Widgets](./3_Widget_Tests/3.2_Mocking_Widgets.md) 20 | - [Testing Individual Widgets](./3_Widget_Tests/3.3_Testing_Individual_Widgets.md) 21 | - [Advanced Widget Testing Topics](./3_Widget_Tests/3.4_Advanced_Widget_Testing_Topics.md) 22 | - [Integration Tests](./4_Integration_Tests/4.1_Introduction_to_Integration_Tests.md) 23 | - [Introduction to Integration Tests](./4_Integration_Tests/4.1_Introduction_to_Integration_Tests.md) 24 | - [Setting Up Integration Tests](./4_Integration_Tests/4.2_Setting_Up_Integration_Tests.md) 25 | - [Tips for Writing Robust Integration Tests](./4_Integration_Tests/4.3_Tips_for_Writing_Robust_Integration_Tests.md) 26 | - [Testing Tips and Best Practices](./5_Testing_Tips_and_Best_Practices/5.1_Organizing_Test_Code.md) 27 | - [Organizing Test Code](./5_Testing_Tips_and_Best_Practices/5.1_Organizing_Test_Code.md) 28 | - [Continuous Integration and Dart](./5_Testing_Tips_and_Best_Practices/5.2_Continuous_Integration_and_Dart.md) 29 | - [Common Pitfalls and How to Avoid Them](./5_Testing_Tips_and_Best_Practices/5.3_Common_Pitfalls_and_How_to_Avoid_Them.md) 30 | - [Special Topics](./6_Special_Topics/6.1_TDD_in_Dart.md) 31 | - [TDD in Dart](./6_Special_Topics/6.1_TDD_in_Dart.md) 32 | - [BDD with Dart](./6_Special_Topics/6.2_BDD_with_Dart.md) 33 | - [Performance Testing](./6_Special_Topics/6.3_Performance_Testing.md) 34 | - [External Resources and Links](./7_External_Resources_and_Links/7.1_Official_Documentation_and_Guides.md) 35 | - [Official Documentation and Guides](./7_External_Resources_and_Links/7.1_Official_Documentation_and_Guides.md) 36 | - [Recommended Books and Courses](./7_External_Resources_and_Links/7.2_Recommended_Books_and_Courses.md) 37 | - [Related Communities and Forums](./7_External_Resources_and_Links/7.3_Related_Communities_and_Forums.md) 38 | 39 | ## How to Contribute 40 | 41 | We welcome contributions from everyone! Please see the [CONTRIBUTING.md](./CONTRIBUTING.md) for guidelines on how to contribute to this repository. 42 | 43 | ## License 44 | 45 | This repository is licensed under the [MIT License](./LICENSE). Please refer to the `LICENSE` file for more details. 46 | 47 | -------------------------------------------------------------------------------- /tex/ch2-unit-tests.tex: -------------------------------------------------------------------------------- 1 | \section{Unit Tests} 2 | \subsection{Basics of Unit Tests} 3 | Unit testing focuses on verifying the correctness of individual units of source code, such as functions or methods, in isolation from the rest of the application. 4 | In this section, we'll break down the fundamental concepts and practices of unit testing in Dart. 5 | 6 | \section*{What is a "Unit"?} 7 | In the context of testing, a "unit" refers to the smallest testable part of any software. 8 | It can be an entire module or just a single function. 9 | The primary goal is to validate that each unit of the software code performs as expected. 10 | 11 | \section*{Why Unit Testing?} 12 | 13 | \begin{enumerate} 14 | \item \textbf{Quick Feedback}: Unit tests are generally fast and can be run frequently, providing immediate feedback to developers. 15 | \item \textbf{Improved Design}: Writing tests often leads to better code design and modularity. 16 | \item \textbf{Easier Refactoring}: Tests ensure that refactoring doesn't introduce regressions. 17 | \item \textbf{Documentation}: Tests can serve as documentation, showcasing how a piece of code is expected to behave. 18 | \end{enumerate} 19 | 20 | \section*{Writing a Unit Test in Dart} 21 | 22 | \fakesubsection{1. Choose the Unit to Test} 23 | Decide on a function or method that you want to test. For this example, let's consider a simple function that returns the sum of two numbers: 24 | 25 | \begin{dartcode} 26 | int sum(int a, int b) { 27 | return a + b; 28 | } 29 | \end{dartcode} 30 | 31 | \fakesubsection{2. Decide on Test Cases} 32 | Think about the different inputs this function can have and what the expected outputs are. 33 | For our sum function: 34 | \begin{itemize} 35 | \item sum(3, 4) should return 7. 36 | \item sum(-3, 4) should return 1. 37 | \end{itemize} 38 | 39 | \begin{dartcode} 40 | import 'package:test/test.dart'; 41 | import 'path_to_your_function.dart'; // Adjust this import path 42 | 43 | void main() { 44 | test('Positive numbers', () { 45 | expect(sum(3, 4), 7); 46 | }); 47 | 48 | test('Mix of negative and positive numbers', () { 49 | expect(sum(-3, 4), 1); 50 | }); 51 | } 52 | \end{dartcode} 53 | Run the tests using \incode{dart test} in your terminal. 54 | 55 | \section*{Mocking in Unit Tests} 56 | Often, you'll want to test units that have external dependencies like databases or APIs. 57 | In unit tests, these dependencies should be isolated using "mocks". Dart's \incode{mockito} package is an excellent tool for this purpose, which we will delve into in a subsequent section. 58 | 59 | \section*{Best Practices} 60 | \begin{enumerate} 61 | \item \textbf{One Assertion per Test}: Ideally, each test should verify just one behavior. 62 | \item \textbf{Descriptive Test Names}: Your test descriptions should explain what the test does, e.g., 'Calculating sum of two positive numbers'. 63 | \item \textbf{Test Edge Cases}: Apart from the usual cases, test boundary and unexpected input cases. 64 | \item \textbf{Keep Tests Independent}: One test should not depend on another. Each test should be standalone. 65 | \end{enumerate} 66 | 67 | \section*{Conclusion} 68 | Unit tests form the backbone of any software testing strategy. 69 | They're vital for ensuring the correctness of individual units of code and building robust applications. 70 | In upcoming sections, we'll explore advanced unit testing techniques, patterns, and tools that are pivotal in Dart. -------------------------------------------------------------------------------- /5_Testing_Tips_and_Best_Practices/5.1_Organizing_Test_Code.md: -------------------------------------------------------------------------------- 1 | # Organizing Test Code in Flutter 2 | Clean, structured, and organized test code is as important as the main codebase. Not only does it make tests more maintainable, but it also ensures that others can understand and contribute easily. This guide will delve into best practices for organizing your test code in Flutter. 3 | 4 | ## 1. Directory Structure 5 | Follow a consistent directory structure that mirrors your main codebase. For instance: 6 | ```lua 7 | my_app/ 8 | |-- lib/ 9 | | |-- src/ 10 | | | |-- models/ 11 | | | |-- views/ 12 | | | |-- controllers/ 13 | |-- test/ 14 | | |-- unit/ 15 | | | |-- models/ 16 | | | |-- controllers/ 17 | | |-- widget/ 18 | | | |-- views/ 19 | | |-- integration/ 20 | ``` 21 | By mirroring the structure, locating corresponding test files becomes intuitive. 22 | 23 | ## 2. File Naming Convention 24 | Naming conventions make it clear at a glance what a file contains. A common approach is to use the name of the component being tested followed by `_test`. 25 | ``` 26 | user_model_test.dart 27 | login_page_test.dart 28 | ``` 29 | 30 | ## 3. Use of setUp and tearDown 31 | These functions, provided by the `test` package, are useful for setting up initial configurations and cleaning up resources after each test. 32 | ```dart 33 | setUp(() { 34 | // Initialization code here 35 | }); 36 | 37 | tearDown(() { 38 | // Cleanup code here 39 | }); 40 | ``` 41 | 42 | ## 4. Grouping Tests 43 | Use the `group` function to logically group related tests, making them more readable and organized. 44 | ```dart 45 | group('Login Tests', () { 46 | test('Valid credentials', () {...}); 47 | test('Invalid credentials', () {...}); 48 | }); 49 | ``` 50 | 51 | ## 5. Mocking & Dependency Separation 52 | Place mocks and fakes in a separate directory or file. This makes it clear which components are real and which are mocked, plus promotes reuse across tests. 53 | ```lua 54 | test/ 55 | |-- mocks/ 56 | | |-- mock_user_service.dart 57 | ``` 58 | 59 | ## 6. Shared Test Utilities 60 | If you have utility functions or shared setup code for multiple tests, consider moving them into shared files. 61 | ```lua 62 | test/ 63 | |-- utils/ 64 | | |-- test_helpers.dart 65 | ``` 66 | 67 | ## 7. Comments & Documentation 68 | Just like your main code, comments can be beneficial in tests, especially when dealing with complex scenarios or edge cases. 69 | ```dart 70 | // Testing edge case where user has no active subscription 71 | test('User without subscription', () {...}); 72 | ``` 73 | ## 8. Keep Tests DRY (Don't Repeat Yourself) 74 | If a piece of setup or assertion logic is repeated across multiple tests, consider factoring it out into a separate function. 75 | 76 | ## 9. Isolate Unit, Widget, and Integration Tests 77 | Separate these tests into distinct directories to ensure clarity and prevent accidental mix-ups. 78 | 79 | ## Conclusion 80 | Organizing test code might seem like a chore initially, but it's an investment that pays off manifold in the long run. As your project grows, structured and organized tests will make maintenance easier, reduce bugs, and help onboard new developers faster. 81 | 82 | In the upcoming sections, we'll dive deeper into advanced testing topics, explore tools and plugins to aid your testing journey, and examine case studies of effective test strategies.[Next](/5_Testing_Tips_and_Best_Practices/5.2_Continuous_Integration_and_Dart.md) 83 | 84 | -------------------------------------------------------------------------------- /5_Testing_Tips_and_Best_Practices/5.2_Continuous_Integration_and_Dart.md: -------------------------------------------------------------------------------- 1 | # Continuous Integration with Dart and Flutter 2 | Continuous Integration (CI) is the practice of merging code changes frequently to the main branch and validating them automatically with tests. When combined with Dart and Flutter applications, CI can ensure consistent code quality and reduce the chances of introducing bugs. This guide provides insights into setting up CI for Dart and Flutter projects. 3 | 4 | ## 1. Benefits of CI for Dart Projects 5 | * **Automated Testing**: Automatically run unit, widget, and integration tests to catch issues early. 6 | * **Consistent Code Quality**: Ensure code adheres to style guidelines and lint rules. 7 | * **Early Bug Detection**: Identify and rectify issues before they reach the production environment. 8 | * **Streamlined Deployments**: Automate the deployment process of applications or packages. 9 | 10 | ## 2. Popular CI Tools for Dart and Flutter 11 | * **GitHub Actions**: Directly integrated with GitHub, it offers powerful workflows for Dart and Flutter. 12 | * **Travis CI**: A popular CI solution with good support for Flutter apps. 13 | * **CircleCI**: Known for its speed and customizability; it also supports Flutter projects. 14 | * **GitLab CI**: If you're using GitLab, its inbuilt CI/CD tools are highly versatile. 15 | 16 | ## 3. Setting up CI 17 | ### Example with GitHub Actions 18 | 1. In your repository, create a `.github/workflows` directory. 19 | 2. Inside, create a file named `dart_ci.yml` or similar. 20 | 3. Define your CI steps: 21 | ```yaml 22 | name: Dart CI 23 | 24 | on: [push, pull_request] 25 | 26 | jobs: 27 | build: 28 | runs-on: ubuntu-latest 29 | steps: 30 | - uses: actions/checkout@v2 31 | - uses: actions/setup-dart@v1 32 | with: 33 | channel: 'stable' 34 | - run: dart pub get 35 | - run: dart analyze 36 | - run: dart test 37 | ``` 38 | This workflow installs Dart, gets the dependencies, analyzes the code for linting errors, and runs the tests. 39 | 40 | ## 4. Handling Dependencies 41 | Caching dependencies can speed up CI build times. Most CI systems provide caching mechanisms. For instance, with GitHub Actions, you can cache the `.pub-cache` directory to speed up subsequent builds. 42 | 43 | ## 5. Flutter-specific CI Tasks 44 | For Flutter, you might want to: 45 | 46 | * Build the app for specific platforms (iOS, Android, web, etc.). 47 | * Run widget tests in headless mode. 48 | * Use `flutter drive` for integration tests. 49 | * Adjust your CI configuration accordingly. 50 | 51 | ## 6. Automate Deployments (Optional) 52 | You can extend CI to Continuous Deployment (CD). For instance, upon merging to the main branch, your CI system could: 53 | 54 | * Deploy a web app to hosting platforms like Firebase Hosting. 55 | * Publish a package to `pub.dev`. 56 | * Build and upload mobile app binaries to app stores. 57 | 58 | ## Conclusion 59 | Implementing CI for Dart and Flutter projects amplifies the benefits of testing, linting, and other quality measures, ensuring that they are consistently applied. While there's an initial overhead in setting up CI, the long-term advantages in terms of code quality, developer productivity, and peace of mind are immeasurable. 60 | 61 | In the next sections, we'll deep-dive into advanced CI/CD techniques, explore best practices in the context of Dart and Flutter, and showcase real-world CI/CD workflows. [Next](/5_Testing_Tips_and_Best_Practices/5.3_Common_Pitfalls_and_How_to_Avoid_Them.md) 62 | 63 | -------------------------------------------------------------------------------- /6_Special_Topics/6.3_Performance_Testing.md: -------------------------------------------------------------------------------- 1 | # Performance Testing in Dart and Flutter 2 | Performance is a crucial factor that can significantly influence user satisfaction and retention. While functional correctness ensures an application does what it's supposed to, performance testing verifies that the application does so in an acceptable time, without consuming excessive resources. Let's explore performance testing in Dart and Flutter. 3 | 4 | ## 1. What is Performance Testing? 5 | Performance testing is a type of testing aimed at determining a system's responsiveness and stability under a particular workload. It can also serve to identify bottlenecks, establish baselines, and ensure compliance with performance criteria. 6 | 7 | ## 2. Types of Performance Testing 8 | * Load Testing: Assess system behavior under anticipated peak load conditions. 9 | * Stress Testing: Evaluate system robustness beyond normal operational capacity, often to the point of failure. 10 | * Endurance Testing: Analyze system performance under expected load over an extended period. 11 | * Spike Testing: Investigate reactions to sudden, large spikes in load. 12 | * Scalability Testing: Determine the system's capacity to scale when additional resources are added. 13 | 14 | ## 3. Performance Testing in Dart 15 | In Dart, especially for backend services, you might focus on: 16 | 17 | * **Response Times**: The time it takes to respond to requests. 18 | * **Throughput**: The number of requests handled per unit of time. 19 | * **Resource Utilization**: How efficiently resources (like CPU, memory) are used. 20 | Tools like `benchmark_harness` can be valuable for Dart VM benchmarks. 21 | 22 | ## 4. Performance Testing in Flutter 23 | Flutter offers a rich set of tools and libraries to help in performance testing: 24 | 25 | * **Flutter Driver**: Allows for the creation of performance tests as part of integration tests. 26 | **Widget-level Benchmarks**: Using benchmark_harness package, you can perform benchmarks for widgets. 27 | * **PerformanceOverlay**: A Flutter widget that displays performance metrics. 28 | 29 | Key Focus Areas in Flutter: 30 | 31 | * **Frame Building Times**: Ensure the smooth rendering of animations. 32 | * **CPU & Memory Usage**: Monitor resource consumption, especially during animations or complex operations. 33 | * **Startup Time**: Measure the time taken from app launch to readiness for user input. 34 | 35 | ## 5. Analyzing Results 36 | After running tests: 37 | 38 | * **Set Baselines**: Understand normal performance metrics to quickly identify deviations in the future. 39 | * **Identify Bottlenecks**: Prioritize issues that significantly degrade performance. 40 | * **Optimize**: Make necessary code or architecture adjustments. 41 | * **Re-test**: Confirm that optimizations have the desired effect without introducing new issues. 42 | 43 | ## 6. Challenges in Performance Testing 44 | * **Environmental Differences**: Discrepancies between testing and production environments can lead to inaccurate results. 45 | * **Dynamic Behavior**: User behavior can be unpredictable, making it hard to emulate realistic conditions. 46 | * **Interdependencies**: External systems, such as databases or APIs, can influence performance. 47 | 48 | ## Conclusion 49 | Performance testing is an essential discipline in software development. For Dart and Flutter developers, it ensures that applications and services not only meet functional requirements but also deliver a seamless, efficient user experience. 50 | 51 | In upcoming sections, we'll provide a deeper dive into tools, best practices, and advanced techniques to master performance testing in Dart and Flutter. [Next](/7_External_Resources_and_Links/7.1_Official_Documentation_and_Guides.md) 52 | -------------------------------------------------------------------------------- /3_Widget_Tests/3.3_Testing_Individual_Widgets.md: -------------------------------------------------------------------------------- 1 | # Testing Individual Widgets in Flutter 2 | As you venture into the world of Flutter, you'll quickly realize the importance of widgets. They are the building blocks of your application. Testing them ensures that each visual and functional element works as expected. This chapter focuses on the specifics of testing individual widgets. 3 | 4 | ## Why Test Individual Widgets? 5 | 1. **Precision**: Targets specific widget behaviors without the noise from surrounding elements. 6 | 2. **Speed**: Faster execution as you're not testing the entire screen or app. 7 | 3. **Isolation**: Ensures that any bugs or issues are isolated to the widget itself. 8 | 9 | ## Getting Started 10 | To test individual widgets, you'll need the flutter_test package. It offers tools like testWidgets for running widget tests and WidgetTester for interacting with widgets. 11 | ```yaml 12 | dev_dependencies: 13 | flutter_test: 14 | sdk: flutter 15 | ``` 16 | ## Basic Widget Test 17 | The essence of a widget test is to: 18 | 19 | 1. Create the widget. 20 | 2. Add it to the widget tree. 21 | 3. Interact with it or check its state. 22 | 4. Verify that it behaves and renders as expected. 23 | 24 | ## Example: Testing a Text Widget 25 | ```dart 26 | void main() { 27 | testWidgets('Displays the correct text', (WidgetTester tester) async { 28 | await tester.pumpWidget(Text('Hello, Flutter!')); 29 | 30 | expect(find.text('Hello, Flutter!'), findsOneWidget); 31 | }); 32 | } 33 | ``` 34 | ## Interactions and Assertions 35 | `WidgetTester` allows you to simulate different interactions like tapping, dragging, and typing. After an interaction, use assertions to check the widget's state. 36 | 37 | ## Example: Testing a RaisedButton 38 | 39 | ```dart 40 | void main() { 41 | testWidgets('Tap on RaisedButton', (WidgetTester tester) async { 42 | bool wasPressed = false; 43 | 44 | await tester.pumpWidget( 45 | MaterialApp( 46 | home: RaisedButton( 47 | onPressed: () => wasPressed = true, 48 | child: Text('Tap me!'), 49 | ), 50 | ), 51 | ); 52 | 53 | await tester.tap(find.byType(RaisedButton)); 54 | await tester.pump(); 55 | 56 | expect(wasPressed, true); 57 | }); 58 | } 59 | ``` 60 | ## Advanced Testing Techniques 61 | ### Using Matchers 62 | Matchers like `findsNothing`, `findsNWidgets(n)`, and `findsWidgets` can help make your assertions more precise. For instance, to check that a widget doesn't exist, use `expect(find.byType(MyWidget), findsNothing)`. 63 | 64 | ### Pumping Widgets 65 | `tester.pump()` triggers a rebuild of the widget tree, reflecting any state changes from the previous frame. In certain cases, you might need `tester.pumpAndSettle()` which repeatedly calls `pump` with the given duration until the widget tree is stable. 66 | 67 | ### Golden Tests 68 | Golden tests (or snapshot tests) involve comparing the widget's rendering with a stored image (a golden file). This helps to check if the UI is rendered correctly and can be particularly useful for custom painted widgets. 69 | ```dart 70 | await tester.pumpWidget(MyFancyWidget()); 71 | await expectLater(find.byType(MyFancyWidget), matchesGoldenFile('golden_file.png')); 72 | ``` 73 | 74 | # Conclusion 75 | Testing individual widgets is a pivotal step in ensuring the robustness of your Flutter applications. Given the modular nature of Flutter's widget tree, having confidence in each building block is essential for the overall reliability of your app. 76 | 77 | In subsequent chapters, dive deeper into integration testing and explore how to ensure complete user flows and interactions are working harmoniously. [Next](/3_Widget_Tests/3.4_Advanced_Widget_Testing_Topics.md) 78 | -------------------------------------------------------------------------------- /3_Widget_Tests/3.2_Mocking_Widgets.md: -------------------------------------------------------------------------------- 1 | # Mocking Widgets in Flutter 2 | Testing widgets often requires simulating certain behaviors or states that are normally triggered by backend data, user inputs, or other external factors. In many cases, directly interacting with these external factors is either challenging or counterproductive. That's where mocking comes into play. This section provides insights into mocking widgets and their dependencies in Flutter. 3 | 4 | ## The Need for Mocking in Widget Tests 5 | Here are some common scenarios where mocking can be beneficial: 6 | 7 | 1. **External Dependencies**: Such as API calls, database operations, or third-party services. 8 | 2. **User Inputs**: Simulating specific user behaviors without manual intervention. 9 | 3. **Specific States**: Testing how a widget behaves under specific conditions, like error states or empty data. 10 | 11 | ## Using mockito with Flutter 12 | `mockito`, which you might be familiar with from Dart unit tests, also plays a crucial role in widget tests. The primary difference lies in how it's used in the context of Flutter's widgets. 13 | 14 | ## Mocking Providers or Services 15 | Imagine you have a widget that fetches user data from an API. You'd likely have a service or provider that manages this. To test the widget in isolation, you'd mock this service or provider. 16 | 17 | For a `UserService` that fetches user data: 18 | ```dart 19 | class UserService { 20 | Future fetchUser(int id) { 21 | // logic to fetch user from API 22 | } 23 | } 24 | ``` 25 | 26 | Using `mockito`, create a mock: 27 | ```dart 28 | class MockUserService extends Mock implements UserService {} 29 | ``` 30 | In your widget test, you can then provide this mock service to your widget using a provider or dependency injection. 31 | 32 | ## Simulating Responses 33 | With the mock service in place, you can dictate its behavior: 34 | ```dart 35 | final userService = MockUserService(); 36 | 37 | // Mock a successful user fetch 38 | when(userService.fetchUser(1)).thenAnswer((_) async => User(id: 1, name: 'John Doe')); 39 | ``` 40 | ## Mocking Widgets 41 | Sometimes, it might be useful to mock entire widgets, especially if they have intricate behaviors or external dependencies themselves. You can achieve this by creating a stub or mock widget to replace the actual widget in tests. 42 | 43 | For instance, if you have a custom `MapWidget` that displays a map and you want to avoid rendering it in certain tests, you could replace it with a simpler Placeholder widget. 44 | 45 | ## Testing with Mocked Data 46 | Once your mocks are set up, you can test how your widget reacts to various data scenarios: 47 | ```dart 48 | testWidgets('Displays user data', (WidgetTester tester) async { 49 | // Use the mocked data setup 50 | await tester.pumpWidget(MyApp(userService: userService)); 51 | 52 | // Check if the user data is displayed 53 | expect(find.text('John Doe'), findsOneWidget); 54 | }); 55 | ``` 56 | 57 | ## Handling Streams and Change Notifiers 58 | Mocking streams or ChangeNotifier classes requires a bit more setup, but the principle is the same. Using mockito, you can mock the stream or methods on the ChangeNotifier and then check how the widget reacts. 59 | 60 | ## Conclusion 61 | Mocking is an invaluable technique when testing widgets in Flutter. By simulating different data states, user interactions, and external dependencies, you can ensure your widgets are robust and handle various scenarios gracefully. As you continue building more complex apps, these testing techniques will become an essential part of your development workflow. 62 | 63 | Up next, delve deeper into advanced widget testing and explore how to test complex UI interactions and flows. [Next](/3_Widget_Tests/3.3_Testing_Individual_Widgets.md) 64 | 65 | -------------------------------------------------------------------------------- /3_Widget_Tests/3.4_Advanced_Widget_Testing_Topics.md: -------------------------------------------------------------------------------- 1 | # Advanced Widget Testing Topics in Flutter 2 | After getting comfortable with basic widget testing, you may find a need to test more complex scenarios, or to optimize and refine your test suites. This chapter will explore advanced topics in widget testing to help you address more intricate challenges. 3 | 4 | ## Advanced Interactions 5 | ### Long Press and Drag 6 | `WidgetTester` offers methods for more complex interactions: 7 | ```dart 8 | await tester.longPress(find.byType(MyWidget)); // Long press 9 | await tester.drag(find.byType(MyWidget), Offset(50, 50)); // Drag by an offset 10 | ``` 11 | 12 | ### Multi-Touch Gestures 13 | To simulate multi-touch gestures like pinch-to-zoom: 14 | ```dart 15 | final firstLocation = tester.getCenter(find.byType(MyWidget)); 16 | final secondLocation = tester.getTopLeft(find.byType(MyWidget)); 17 | await tester.zoom(pinchStart: firstLocation, pinchEnd: secondLocation, scale: 2.5); 18 | ``` 19 | 20 | ### Scrolling Widgets 21 | To test widgets that scroll, like ListView or GridView: 22 | ```dart 23 | await tester.scrollUntilVisible(find.text('item $index'), Offset(0, 500), scrollable: find.byType(Scrollable); // Scroll by an offset 24 | await tester.fling(find.byType(ListView), Offset(0, -500), 2500); // Fling/quick scroll 25 | await tester.pumpAndSettle(); 26 | ``` 27 | 28 | ### Testing Animations 29 | Animations might require additional considerations: 30 | 31 | 1. **Pumping Frames**: To move forward in an animation, use `tester.pump(Duration(milliseconds: x))`. 32 | 2. **Evaluating States**: Check widget states at different points in an animation. 33 | Example of testing a `FadeTransition`: 34 | ```dart 35 | final fadeTransition = FadeTransition(opacity: animationController, child: MyWidget()); 36 | await tester.pumpWidget(fadeTransition); 37 | 38 | expect(myWidgetFinder, findsOneWidget); 39 | 40 | // Begin the animation 41 | animationController.forward(); 42 | await tester.pumpAndSettle(); 43 | 44 | // Check after animation completes 45 | expect(myWidgetFinder, findsNothing); 46 | ``` 47 | 48 | ### Custom Matchers 49 | You can create custom matchers to help with more specific test conditions. For example, to check if a widget's size conforms to expected values: 50 | ```dart 51 | Matcher hasSize(Size size) => MatchesWidgetData((widget) => widget.size == size); 52 | expect(find.byType(MyWidget), hasSize(Size(100, 100))); 53 | ``` 54 | 55 | ### Working with Keys 56 | Using keys, especially `ValueKey`, can make finding widgets in tests much easier: 57 | ```dart 58 | final myKey = ValueKey('my_widget_key'); 59 | MyWidget(key: myKey); 60 | ``` 61 | In tests: 62 | ```dart 63 | find.byKey(myKey); 64 | ``` 65 | This can be especially helpful when differentiating between multiple instances of the same widget type. 66 | 67 | ### Grouping Tests 68 | As your test suite grows, structuring your tests using groups can improve readability: 69 | ```dart 70 | group('FlatButton Tests', () { 71 | testWidgets('Displays text', (WidgetTester tester) async { 72 | ... 73 | }); 74 | 75 | testWidgets('Handles onTap', (WidgetTester tester) async { 76 | ... 77 | }); 78 | }); 79 | ``` 80 | 81 | ### Conclusion 82 | Advanced widget testing in Flutter can seem complex, but by taking advantage of the rich set of tools provided by the framework, you can ensure your UI is robust and responds correctly under various scenarios. 83 | 84 | As you dive deeper into the testing ecosystem, remember that the balance between thorough testing and maintainability is crucial. Always aim for tests that are comprehensive yet flexible enough to adapt as your app evolves. 85 | 86 | Up next, venture into integration tests to explore comprehensive testing of full app flows and interactions! [Next](/4_Integration_Tests/4.1_Introduction_to_Integration_Tests.md) 87 | -------------------------------------------------------------------------------- /tex/preamble.tex: -------------------------------------------------------------------------------- 1 | \usepackage{url} 2 | \usepackage{hyperref} 3 | \usepackage{cleveref} 4 | \usepackage{fontenc} 5 | \usepackage[usenames,svgnames,dvipsnames]{xcolor} 6 | \usepackage{listings} 7 | \usepackage[outputdir=build]{minted} 8 | % \usepackage{pygmentex} 9 | \usepackage{tcolorbox} 10 | 11 | 12 | \setmintedinline{breaklines} 13 | 14 | \newcommand{\incode}[1]{\mintinline[breakanywhere]{c++}|#1|} 15 | 16 | % \setmonofont{Inconsolata} 17 | 18 | \tcbuselibrary{listings, minted, skins} 19 | 20 | \tcbset{listing engine=minted} 21 | 22 | % % \usemintedstyle{one-dark} 23 | % % \setmonofont{Consolas} 24 | 25 | \newtcblisting{bashcode}{ 26 | listing only, 27 | minted language=bash, 28 | minted style=murphy, 29 | % colback=bg, 30 | enhanced, 31 | frame hidden, 32 | skin=tile, 33 | width=\textwidth, 34 | top=6pt,bottom=6pt,left=6pt,right=2pt, 35 | minted options={ 36 | % fontfamily=fdm, 37 | % fontsize=\footnotesize, 38 | tabsize=2, breaklines, gobble=0} 39 | } 40 | 41 | \newtcblisting{yamlcode}{ 42 | listing only, 43 | minted language=yaml, 44 | minted style=gruvbox-dark, 45 | colback=bg, 46 | enhanced, 47 | frame hidden, 48 | skin=tile, 49 | width=\textwidth, 50 | top=6pt,bottom=6pt,left=6pt,right=2pt, 51 | minted options={ 52 | % fontfamily=fdm, 53 | % fontsize=\footnotesize, 54 | tabsize=1, breaklines, gobble=0} 55 | } 56 | 57 | \newtcblisting{dartcode}{ 58 | listing only, 59 | minted language=dart, 60 | minted style=one-dark, 61 | colback=bg, 62 | enhanced, 63 | frame hidden, 64 | skin=tile, 65 | width=\textwidth, 66 | top=6pt,bottom=6pt,left=6pt,right=2pt, 67 | minted options={ 68 | % fontfamily=fdm, 69 | % fontsize=\footnotesize, 70 | tabsize=1, breaklines, gobble=0} 71 | } 72 | 73 | % \definecolor{inline}{RGB}{187,57,82} 74 | \definecolor{bg}{RGB}{30,30,46} 75 | % \setminted[bash]{bgcolor=bg} 76 | 77 | \usemintedstyle{one-dark} 78 | 79 | % \newenvironment{bashcode}{ 80 | % \begin{minted}[style=one-dark]{bash} 81 | % } 82 | % { 83 | % \end{minted} 84 | % } 85 | 86 | 87 | 88 | \hypersetup{ 89 | linkcolor={red!50!black}, 90 | citecolor={green!50!black}, 91 | urlcolor={blue!80!black}, 92 | pdfkeywords={napkin,math}, 93 | pdfsubject={web.evanchen.cc}, 94 | colorlinks, 95 | pdfusetitle, 96 | } 97 | 98 | \newcommand{\tddversion}{v1.0.\hbox{\the\year\twodigits\month\twodigits\day}} 99 | 100 | \usepackage[headsepline]{scrlayer-scrpage} 101 | % \renewcommand{\headfont}{} 102 | % \addtolength{\textheight}{3.14cm} 103 | % \setlength{\footskip}{0.5in} 104 | % \setlength{\headsep}{10pt} 105 | 106 | \def\shortdate{\leavevmode\hbox{\the\year-\twodigits\month-\twodigits\day}} 107 | \def\twodigits#1{\ifnum#1<10 0\fi\the#1} 108 | % \automark[chapter]{chapter} 109 | 110 | \rohead{\footnotesize\thepage} 111 | \rehead{\footnotesize \textbf{\sffamily Test Driven Dart} (\tddversion)} 112 | \lehead{\footnotesize\thepage} 113 | \lohead{\footnotesize \leftmark} 114 | \chead{} 115 | \rofoot{} 116 | \refoot{} 117 | \lefoot{} 118 | \lofoot{} 119 | %\cfoot{\pagemark} 120 | 121 | %%fakesection Fancy section and chapter heads 122 | \renewcommand*{\sectionformat}{\color{teal}\S\thesection\autodot\enskip} 123 | \renewcommand*{\subsectionformat}{\color{cyan}\S\thesubsection\autodot\enskip} 124 | % \renewcommand{\thesubsection}{\thesection.\roman{subsection}} 125 | 126 | % \addtokomafont{chapterprefix}{\raggedleft} 127 | % \RedeclareSectionCommand[beforeskip=0.5em]{chapter} 128 | % \renewcommand*{\chapterformat}{% 129 | % \mbox{\scalebox{1.5}{\chapappifchapterprefix{\nobreakspace}}% 130 | % \scalebox{2.718}{\color{purple}\thechapter\autodot}\enskip}} 131 | 132 | % \addtokomafont{partprefix}{\rmfamily} 133 | % \renewcommand*{\partformat}{\color{purple}\scalebox{2.5}{\thepart}} 134 | 135 | \setlength{\parindent}{0pt} 136 | 137 | \newcommand{\fakesubsection}[1]{\large{\textbf{#1}}\\} 138 | 139 | \newcommand{\fakelinklistitem}[3]{\href{#2}{\textbf{#1}}: #3} 140 | -------------------------------------------------------------------------------- /tex/ch1-getting-started.tex: -------------------------------------------------------------------------------- 1 | \section{Getting Started}\label{getting-started} 2 | 3 | \subsection{Introduction to Testing in Dart} 4 | 5 | Welcome to the introduction section of Test Driven Dart! Before we dive deep into various testing paradigms, let's establish a foundational understanding of why testing is critical, especially in a language as versatile as Dart. 6 | 7 | \subsubsection*{Why Testing Matters} 8 | 9 | Testing is not just about ensuring the correctness of code – it's about assuring the quality of the end product, saving costs in the long term, and providing confidence when making changes. 10 | 11 | \begin{enumerate} 12 | \item \textbf{Code Quality Assurance}: Well-tested code tends to have fewer bugs, ensuring that the functionalities are working as expected. 13 | \item \textbf{Long-term Savings}: Addressing bugs during development is cheaper than addressing them after the software is released. 14 | \item \textbf{Confidence in Refactoring}: With comprehensive tests, developers can make changes without the fear of breaking existing functionalities. 15 | \item \textbf{Documentation}: Tests provide an excellent documentation source, as they demonstrate how the code is supposed to work. 16 | \end{enumerate} 17 | 18 | \subsubsection*{Testing in Dart} 19 | 20 | Dart, with its growing ecosystem and the backing of the Flutter framework, has seen a surge in its user base. 21 | This growth makes it even more important to establish robust testing practices. 22 | 23 | \begin{itemize} 24 | \item \textbf{Rich Library Support}: Dart has built-in libraries, such as \incode{package:test}, that provide tools to write unit tests, widget tests, and more. 25 | \item \textbf{Flexibility}: Dart supports testing for both web and mobile applications, thanks to its versatile runtime. 26 | \item \textbf{Integrated with Flutter}: For mobile developers using Flutter, Dart's testing capabilities are tightly integrated, allowing for widget testing and UI testing. 27 | \end{itemize} 28 | 29 | \subsubsection*{Test Driven Development (TDD)} 30 | 31 | Given our focus on "Test Driven Dart", it's essential to touch upon TDD briefly: 32 | 33 | \noindent TDD is a software development approach where tests are written before the actual code. The process follows a quick iteration of these three steps: 34 | \begin{enumerate} 35 | \item \textbf{Write a failing test}: Define what you expect a particular functionality to achieve but don't implement the functionality yet. 36 | \item \textbf{Make the test pass}: Implement just enough code to make the test pass. 37 | \item \textbf{Refactor}: Once the test is passing, optimize and clean up the code. 38 | \end{enumerate} 39 | In the upcoming sections, we'll dive deeper into TDD, exploring its benefits and seeing it in action with Dart. 40 | 41 | \subsubsection*{Conclusion} 42 | Testing is a critical aspect of software development. With Dart, developers have a powerful and flexible platform to write and execute tests across various platforms. As we move forward in this guide, you'll learn the specifics of writing tests in Dart, emphasizing a test-driven approach. 43 | 44 | Up next, we'll be setting up our testing environment for Dart. Let's move on! 45 | 46 | \subsection{Setting Up Testing Environment for Dart}\label{setting-up-testing-environment-for-dart} 47 | 48 | In this section, we'll walk you through setting up a testing environment for Dart applications. Having a well-configured environment is crucial for smooth test writing and execution. 49 | 50 | \subsubsection*{Prerequisites} 51 | Before we begin, make sure you have: 52 | 53 | \begin{itemize} 54 | \item Dart SDK installed. If not, you can download it from \href{https://dart.dev/get-dart}{Dart's official website}. 55 | \item A code editor of your choice. While Dart is supported in many editors, \href{https://code.visualstudio.com/}{Visual Studio Code} and \href{https://www.jetbrains.com/idea/}{IntelliJ IDEA} are recommended due to their excellent Dart and Flutter plugin support. 56 | \end{itemize} 57 | 58 | \subsubsection*{Step-by-Step Setup} 59 | 60 | \large{\textbf{1. Create a New Dart Project (Optional)}}\\ 61 | If you're starting from scratch: 62 | 63 | \begin{bashcode} 64 | dart create my_test_project 65 | cd my_test_project 66 | \end{bashcode} 67 | 68 | This will generate a new Dart project in a directory named \incode{my_test_project}. 69 | \\[1em] 70 | \noindent\large{\textbf{2. Adding the Test Package}}\\ 71 | Add the test package to your \incode{pubspec.yaml} under dev\_dependencies: 72 | 73 | \begin{yamlcode} 74 | dev_dependencies: 75 | test: ^any_version 76 | \end{yamlcode} 77 | 78 | Run \incode{dart pub get} to install the new dependency. 79 | \\[1em] 80 | \noindent\large{\textbf{3. Creating a Test Directory}} 81 | By convention, Dart applications have a `test` directory at the root level for all test files. If it doesn't exist, create it: 82 | 83 | \begin{bashcode} 84 | mkdir test 85 | \end{bashcode} 86 | % \\[1em] 87 | 88 | \noindent\large{\textbf{4. Writing Your First Test}} 89 | Inside the test directory, create a new file named \incode{sample_test.dart} and add the following content: 90 | 91 | \begin{dartcode} 92 | import 'package:test/test.dart'; 93 | 94 | void main() { 95 | test('String split', () { 96 | var string = 'foo,bar,baz'; 97 | expect(string.split(','), equals(['foo', 'bar', 'baz'])); 98 | }); 99 | } 100 | \end{dartcode} 101 | 102 | \noindent\large{\textbf{5. Running the Test}} 103 | Navigate to the root directory of your project in the terminal and run: 104 | 105 | \begin{bashcode} 106 | dart test 107 | \end{bashcode} 108 | This will execute all tests in the test directory. You should see a message indicating that the test passed. 109 | 110 | \subsubsection*{Tips for a Smooth Testing Experience} 111 | \begin{itemize} 112 | \item rganize your Tests: As your project grows, consider organizing tests in folders within the test directory based on functionalities or modules. 113 | \item Use Descriptive Test Names: Always name your tests descriptively to make it easy for other developers (or future you) to understand the purpose of each test. 114 | \item Continuous Integration (CI): Consider setting up a CI pipeline to automatically run tests whenever you push code changes. 115 | \end{itemize} 116 | 117 | \subsubsection*{Conclusion} 118 | Setting up a testing environment for Dart is straightforward, thanks to its well-designed tools and packages. 119 | Now that you've laid down the groundwork, you're ready to dive deeper into the world of Dart testing. 120 | 121 | In the next section, we'll explore the basic structure of a Dart test. Onward! 122 | 123 | \subsection{Basic Test Structure in Dart} 124 | Now that we've set up our testing environment, let's delve into the basic structure of a Dart test. 125 | Understanding this foundation will aid you as you explore more advanced testing topics. 126 | 127 | \subsubsection*{Anatomy of a Dart Test} 128 | A typical Dart test file contains a series of \incode{test} functions that each represent a single test case. Here's a simple breakdown:\\[1em] 129 | \noindent\large{\textbf{1. Import the Test Package}}\\ 130 | 131 | \begin{dartcode} 132 | import 'package:test/test.dart'; 133 | \end{dartcode} 134 | 135 | This imports the necessary functions and utilities to write tests.\\[1em] 136 | \large{\textbf{2. Main Function}}\\ 137 | Every Dart test file begins with a \incode{main} function. It acts as an entry point for the test runner. 138 | \begin{dartcode} 139 | void main() { 140 | // Your tests go here 141 | } 142 | \end{dartcode} 143 | \large{\textbf{3. The test Function}}\\ 144 | The \incode{test} function is where you define individual test cases. It takes two arguments: 145 | 146 | \begin{itemize} 147 | \item A description of the test (String). 148 | \item A callback function containing the test code. 149 | \end{itemize} 150 | 151 | \begin{dartcode} 152 | test('Description of the test', () { 153 | // Test code here 154 | }); 155 | \end{dartcode} 156 | 157 | \fakesubsection{4. Making Assertions with expect} 158 | Within the test callback function, you use the \incode{expect} function to assert that a value meets certain criteria. 159 | \begin{dartcode} 160 | test('String splitting', () { 161 | var string = 'foo,bar,baz'; 162 | expect(string.split(','), equals(['foo', 'bar', 'baz'])); 163 | }); 164 | \end{dartcode} 165 | In this example, \incode{string.split(',')} is the actual value, and \incode{equals(['foo', 'bar', 'baz'])} is the matcher that defines the expected value. 166 | 167 | \subsubsection*{Grouping Tests} 168 | As your testing suite grows, organizing related tests into groups can be beneficial. Use the \incode{group} function: 169 | \begin{dartcode} 170 | group('String tests', () { 171 | test('String splitting', () { 172 | var string = 'foo,bar,baz'; 173 | expect(string.split(','), equals(['foo', 'bar', 'baz'])); 174 | }); 175 | 176 | // Other string-related tests 177 | \end{dartcode} 178 | 179 | \subsubsection*{Conclusion} 180 | The basic structure of a Dart test is both intuitive and expressive. As you progress in your Dart testing journey, you'll encounter more advanced utilities and functions to handle diverse scenarios. But the principles we covered in this section will always remain fundamental. 181 | 182 | Up next, we'll dive into unit testing in Dart, exploring how to test individual pieces of logic in isolation. 183 | 184 | Stay tuned! 185 | -------------------------------------------------------------------------------- /tex/ch4-integration-tests.tex: -------------------------------------------------------------------------------- 1 | \section{Integration Tests} 2 | 3 | \subsection{Introduction to Integration Tests in Flutter} 4 | While unit and widget tests are critical for ensuring the correctness of individual pieces of your application, integration tests focus on testing larger chunks or the entire application itself. 5 | This ensures that all parts work together harmoniously, yielding the desired overall behavior. 6 | 7 | \subsection*{What are Integration Tests?} 8 | 9 | Integration tests in Flutter are tests that ensure that multiple parts of your app work together correctly. 10 | They often: 11 | 12 | \begin{enumerate} 13 | \item Run the entire app. 14 | \item Simulate user behavior (like tapping, scrolling, and keying in text). 15 | \item Ensure that these interactions yield the desired results. 16 | \end{enumerate} 17 | 18 | \subsection*{Why Integration Testing?} 19 | 20 | \fakesubsection{1. Holistic Application Behavior:} 21 | Ensure that the entire system behaves as expected when different pieces come together. 22 | 23 | \fakesubsection{2. User Flow Verification:} 24 | Check if the overall user experience is smooth and the app behaves correctly through user scenarios or stories. 25 | 26 | \fakesubsection{3. Detecting Regression:} 27 | Identify any unintentional side effects that might arise when making changes in the codebase. 28 | 29 | \subsubsection*{Setting Up} 30 | 31 | To start with integration testing in Flutter, you'll need the \incode{integration_test} package. 32 | 33 | \begin{yamlcode} 34 | dev_dependencies: 35 | integration_test: 36 | sdk: flutter 37 | \end{yamlcode} 38 | 39 | \subsubsection*{Writing Your First Integration Test} 40 | 41 | Integration tests reside in the \incode{integration_test} folder and often use both the \incode{test} and \incode{flutter_test} libraries. 42 | 43 | Example structure: 44 | 45 | \begin{dartcode} 46 | import 'package:integration_test/integration_test.dart'; 47 | import 'package:flutter_test/flutter_test.dart'; 48 | import 'package:my_app/main.dart'; 49 | 50 | void main() { 51 | IntegrationTestWidgetsFlutterBinding.ensureInitialized(); 52 | 53 | group('Main App Flow', () { 54 | testWidgets('Navigating through the app', (tester) async { 55 | // Start the app 56 | await tester.pumpWidget(MyApp()); 57 | 58 | // Interact with the app 59 | await tester.tap(find.text('Next')); 60 | await tester.pumpAndSettle(); 61 | 62 | // Assertions 63 | expect(find.text('Page 2'), findsOneWidget); 64 | }); 65 | }); 66 | } 67 | \end{dartcode} 68 | 69 | \subsubsection*{Running Integration Tests} 70 | 71 | Integration tests can be run on both real devices and emulators. Use the following command: 72 | 73 | \begin{bashcode} 74 | flutter test integration_test/my_test.dart 75 | \end{bashcode} 76 | 77 | For more advanced scenarios, you might want to look into the \incode{flutter drive} command. 78 | 79 | \subsection*{Conclusion} 80 | 81 | Integration tests are a vital part of ensuring that your app works as a cohesive unit. 82 | While they might take longer to run than unit or widget tests, they offer assurance that your app works correctly from the user's perspective. 83 | 84 | In subsequent chapters, we'll delve deeper into advanced integration testing topics, automation, and best practices to get the most out of your testing efforts. 85 | 86 | 87 | \subsection{Setting Up Integration Tests in Flutter} 88 | 89 | Integration tests provide a comprehensive approach to verifying the correct functioning of your Flutter applications from a holistic perspective. Before writing and running these tests, though, you need to set them up correctly. 90 | This guide will walk you through the setup process step-by-step. 91 | 92 | \subsection*{Step 1: Dependencies} 93 | 94 | First, you'll need to add the necessary dependencies to your \incode{pubspec.yaml}: 95 | 96 | \begin{yamlcode} 97 | dev_dependencies: 98 | integration_test: 99 | sdk: flutter 100 | flutter_test: 101 | sdk: flutter 102 | \end{yamlcode} 103 | 104 | Run \incode{flutter pub get} to fetch the required packages. 105 | 106 | \subsection*{Step 2: Directory Structure} 107 | 108 | It's a good practice to organize your integration tests in a separate directory to keep them distinct from unit and widget tests. Create an \incode{integration_test} directory at the root level of your project. 109 | 110 | \begin{yamlcode} 111 | my_app/ 112 | |-- lib/ 113 | |-- test/ 114 | |-- integration_test/ 115 | | |-- app_test.dart 116 | |-- pubspec.yaml 117 | \end{yamlcode} 118 | 119 | \subsection*{Step 3: Configuration} 120 | 121 | Start by importing the necessary libraries and initializing the integration test widgets binding. 122 | This ensures your tests have the resources they need to execute correctly. 123 | 124 | \begin{dartcode} 125 | // app_test.dart 126 | import 'package:integration_test/integration_test.dart'; 127 | import 'package:flutter_test/flutter_test.dart'; 128 | import 'package:my_app/main.dart'; 129 | 130 | void main() { 131 | IntegrationTestWidgetsFlutterBinding.ensureInitialized(); 132 | 133 | // Your integration tests go here... 134 | } 135 | \end{dartcode} 136 | 137 | \subsection*{Step 4: Writing a Basic Test} 138 | 139 | Within your \incode{main} function, you can begin defining tests. Here's a simple example where we launch the app and check if the homepage is displayed: 140 | 141 | \begin{dartcode} 142 | testWidgets('Homepage displays correctly', (tester) async { 143 | await tester.pumpWidget(MyApp()); 144 | 145 | // Check if homepage title exists 146 | expect(find.text('Homepage'), findsOneWidget); 147 | }); 148 | \end{dartcode} 149 | 150 | \subsection*{Step 5: Running the Tests} 151 | 152 | To execute integration tests, use the \incode{flutter test} command, specifying the path to your integration test file: 153 | 154 | \begin{bashcode} 155 | flutter test integration_test/app_test.dart 156 | \end{bashcode} 157 | 158 | For more complex scenarios involving multiple devices, you might use the \incode{flutter drive} command. 159 | 160 | \subsection*{Step 6: Continuous Integration (Optional)} 161 | 162 | For larger projects, you may wish to automate your integration tests using a Continuous Integration (CI) platform like GitHub Actions, Travis CI, or CircleCI. 163 | This will automatically run your tests on every commit, ensuring constant feedback and early bug detection. 164 | 165 | \subsection*{Conclusion} 166 | 167 | Setting up integration tests in Flutter might seem like a few extra steps in the beginning, but the confidence these tests provide in ensuring your app's overall behavior is invaluable. 168 | As your app grows, these tests will serve as a safety net, helping catch issues that unit or widget tests might miss. 169 | 170 | In the upcoming sections, we'll delve deeper into writing complex integration tests, simulating user interactions, and best practices to ensure you extract maximum value from your tests. 171 | 172 | \subsection{Tips for Writing Robust Integration Tests in Flutter} 173 | 174 | Writing integration tests is one thing; ensuring they're robust, maintainable, and effective is another. 175 | This guide offers tips and best practices to bolster the resilience and usefulness of your integration tests in Flutter. 176 | 177 | \subsection*{1. Use Descriptive Test Names} 178 | 179 | Clear test names make it easier to identify the test purpose and debug if they fail. 180 | 181 | \begin{dartcode} 182 | testWidgets('Should navigate to user profile when tapping avatar', (tester) async { ... }); 183 | \end{dartcode} 184 | 185 | \subsection*{2. Utilize Keys} 186 | 187 | Assign \incode{Key} values to your widgets, especially when they're dynamically generated. It makes them easier to locate during testing. 188 | 189 | \begin{dartcode} 190 | ListView.builder( 191 | itemBuilder: (context, index) => ListTile(key: ValueKey('item_$index'), ...), 192 | ); 193 | \end{dartcode} 194 | 195 | In tests: 196 | 197 | \begin{dartcode} 198 | await tester.tap(find.byKey(ValueKey('item_2'))); 199 | \end{dartcode} 200 | 201 | \subsection*{3. Avoid Magic Numbers} 202 | 203 | Use named constants to define timeouts, index values, or any other numbers in tests. 204 | 205 | \begin{dartcode} 206 | const defaultTimeout = Duration(seconds: 10); 207 | \end{dartcode} 208 | 209 | \subsection*{4. Opt for pumpAndSettle Wisely} 210 | 211 | While \incode{pumpAndSettle} can be useful, it might lead to flakiness or longer test run times. 212 | Sometimes, it's better to use \incode{pump} with specific durations. 213 | 214 | \subsection*{5. Check Multiple States} 215 | 216 | Beyond checking the final state, ensure intermediate states in a flow are as expected. This can help catch issues where the final state is correct, but the journey there isn't. 217 | 218 | \subsection*{6. Limit External Dependencies} 219 | 220 | If your integration tests rely heavily on external services or databases, they can become slow or flaky. 221 | Mock these services or use test doubles when possible. 222 | 223 | \subsection*{7. Run on Different Devices and Orientations} 224 | 225 | Differences in screen sizes, resolutions, or orientations can cause unexpected behavior. 226 | Consider running tests on various emulators and real devices. 227 | 228 | \subsection*{8. Group Related Tests} 229 | 230 | Utilize \incode{group} to bundle related tests together. This aids in readability and organization. 231 | 232 | \begin{dartcode} 233 | group('User Profile Tests', () { 234 | testWidgets('Displays user info', ...); 235 | testWidgets('Updates on edit', ...); 236 | }); 237 | \end{dartcode} 238 | 239 | \subsection*{9. Refrain from Over-Testing} 240 | 241 | Avoid writing integration tests for every possible scenario, especially if it's already covered by unit or widget tests. 242 | Focus on critical user journeys. 243 | 244 | \subsection*{10. Stay Updated} 245 | 246 | Flutter is rapidly evolving, and new testing functionalities or best practices may emerge. 247 | Regularly check Flutter's official documentation and the broader community's insights. 248 | 249 | \subsection*{Conclusion} 250 | 251 | Crafting robust integration tests is a mix of understanding your application's architecture, predicting user behavior, and adopting good testing practices. 252 | With the tips mentioned above, you'll be well-equipped to write resilient tests that offer meaningful feedback and ensure your application's reliability from a holistic standpoint. 253 | 254 | In the coming chapters, we'll explore more advanced integration testing scenarios, dive deeper into automation, and examine techniques for enhancing your test suite's efficiency. 255 | 256 | 257 | 258 | 259 | 260 | -------------------------------------------------------------------------------- /tex/ch7-external-resources-and-links.tex: -------------------------------------------------------------------------------- 1 | \section{External Resources and Links} 2 | \subsection{Official Documentation and Guides for Dart and Flutter Testing} 3 | 4 | Understanding and leveraging official documentation is key to becoming proficient in any framework or language. 5 | Dart and Flutter have comprehensive official guides and API references that are invaluable to developers. 6 | In this section, we'll provide an overview and curated list of these resources. 7 | 8 | \subsection*{1. Why Use Official Documentation?} 9 | 10 | \begin{itemize} 11 | \item \textbf{Accuracy}: Content is maintained by experts and typically undergoes rigorous review. 12 | \item \textbf{Up-to-date}: As Dart and Flutter evolve, so does the documentation, ensuring relevance. 13 | \item \textbf{Comprehensiveness}: Covers everything from basic topics to advanced techniques. 14 | \item \textbf{Examples}: Contains practical, executable examples that help solidify understanding. 15 | \end{itemize} 16 | 17 | \subsection*{2. Dart Testing} 18 | 19 | \subsubsection*{Dart Test Package} 20 | 21 | Dart provides a unit testing framework via the \href{https://pub.dev/packages/test}{\incode{test}} package. 22 | 23 | \begin{itemize} 24 | \item \href{https://pub.dev/packages/test#-readme-tab-}{\textbf{Getting Started}}: Introduction to setting up and writing basic tests. 25 | \item \href{https://github.com/dart-lang/test/blob/master/pkgs/test/doc/configuration.md}{\textbf{Configuration}}: Dive deep into configuring test suites for various needs. 26 | \end{itemize} 27 | 28 | \subsubsection*{Mocking in Dart} 29 | 30 | Using the href{https://pub.dev/packages/mockito}{\incode{mockito}} package, simulate the behavior of real objects in controlled ways. 31 | \begin{itemize} 32 | \item \href{https://pub.dev/packages/mockito}{\textbf{Mockito Basics}}: Learn how to create and use mock objects. 33 | \end{itemize} 34 | 35 | \subsection*{3. Flutter Testing} 36 | 37 | Flutter provides a rich set of testing utilities that cater to different layers, from widget testing to integration testing. 38 | 39 | \fakesubsection{Flutter Test Package} 40 | 41 | The foundational package for all testing activities in Flutter. 42 | 43 | \begin{itemize} 44 | \item \href{https://docs.flutter.dev/testing}{\textbf{Introduction to Testing}}: A broad overview of testing in Flutter. 45 | \item \href{https://docs.flutter.dev/cookbook/testing/unit/introduction}{\textbf{Unit Testing with Flutter}}: Guidelines for writing unit tests. 46 | \item \href{https://docs.flutter.dev/cookbook/testing/widget/introduction}{\textbf{Widget Testing}}: Dive into the nuances of testing Flutter widgets. 47 | \item \href{https://docs.flutter.dev/cookbook/testing/integration/introduction}{\textbf{Integration Testing}}: Understand testing complete flows or interactions. 48 | \end{itemize} 49 | 50 | \subsection*{Flutter Performance Testing} 51 | 52 | Understanding and monitoring the performance of your Flutter apps is essential. 53 | 54 | \begin{itemize} 55 | \item \fakelinklistitem{Performance Profiling}{https://flutter.dev/docs/testing/ui-performance}{Tools and tips for profiling app performance.} 56 | \end{itemize} 57 | 58 | \subsection*{4. Additional Resources} 59 | 60 | \begin{itemize} 61 | \item \fakelinklistitem{Effective Dart}{https://dart.dev/effective-dart}{Best practices for coding, designing, and testing Dart code.} 62 | \fakelinklistitem{Flutter Samples}{https://github.com/flutter/samples}{A GitHub repository filled with Flutter samples, including various testing examples.} 63 | \end{itemize} 64 | 65 | \subsection*{Conclusion} 66 | 67 | Embracing the wealth of official documentation and guides is a surefire way to enhance your Dart and Flutter testing skills. While other resources, tutorials, and community contributions are valuable, the official docs act as a cornerstone for understanding and best practices. 68 | 69 | 70 | \subsection{Recommended Books and Courses on Dart, Flutter, and Testing} 71 | 72 | There's a plethora of learning resources available, spanning various formats. 73 | Books offer in-depth knowledge, while online courses provide an interactive experience with potential hands-on exercises. 74 | This section curates a list of notable books and courses tailored for Dart, Flutter, and software testing enthusiasts. 75 | 76 | \subsection*{1. Books on Dart and Flutter} 77 | 78 | \subsubsection*{Dart} 79 | 80 | \begin{enumerate} 81 | \item \textbf{"Dart: Up and Running"} by Kathy Walrath and Seth Ladd 82 | \begin{itemize} 83 | \item An introductory guide to Dart, covering the basics and diving into more advanced topics. 84 | \end{itemize} 85 | \item \textbf{"Dart for Absolute Beginners"} by David Kopec 86 | \begin{itemize} 87 | \item A beginner-friendly approach to Dart programming, perfect for those new to the language. 88 | \end{itemize} 89 | \end{enumerate} 90 | 91 | \subsubsection*{Flutter} 92 | \begin{enumerate} 93 | \item \textbf{"Flutter in Action"} by Eric Windmill 94 | \begin{itemize} 95 | \item Comprehensive coverage of Flutter, from setting up to building complex apps. 96 | \end{itemize} 97 | 98 | \item \textbf{"Beginning Flutter: A Hands-On Guide to App Development"} by Marco L. Napoli 99 | \begin{itemize} 100 | \item Step-by-step guide to building Flutter applications, ideal for beginners. 101 | \end{itemize} 102 | \end{enumerate} 103 | 104 | \subsection*{2. Books on Software Testing} 105 | 106 | \begin{enumerate} 107 | \item \textbf{"Clean Code: A Handbook of Agile Software Craftsmanship"} by Robert C. Martin 108 | \begin{itemize} 109 | \item While not exclusively on testing, it covers writing maintainable and testable code. 110 | \end{itemize} 111 | 112 | \item \textbf{"Test Driven Development: By Example"} by Kent Beck 113 | \begin{itemize} 114 | \item A classic read on the TDD methodology and its practical implementation. 115 | \end{itemize} 116 | \item \textbf{"Pragmatic Unit Testing in Java with JUnit"} by Andy Hunt and Dave Thomas 117 | \begin{itemize} 118 | \item Offers insights into unit testing which can be extrapolated to Dart and Flutter environments. 119 | \end{itemize} 120 | \end{enumerate} 121 | 122 | \subsection*{3. Courses on Dart and Flutter Testing} 123 | 124 | \begin{enumerate} 125 | \item \textbf{"Dart and Flutter: The Complete Developer's Guide"} on Udemy by Stephen Grider 126 | \begin{itemize} 127 | \item Comprehensive coverage of Dart and Flutter, with dedicated sections on testing. 128 | \end{itemize} 129 | 130 | \item \textbf{"Flutter Testing Masterclass"} on Udacity 131 | \begin{itemize} 132 | \item A deep dive into Flutter testing methodologies, from unit to integration testing. 133 | \end{itemize} 134 | \item \textbf{"Mastering Dart Testing"} on Pluralsight 135 | \begin{itemize} 136 | \item Focuses on advanced testing techniques, patterns, and best practices in Dart. 137 | \end{itemize} 138 | \end{enumerate} 139 | 140 | \subsection*{4. Additional Learning Resources} 141 | 142 | \begin{enumerate} 143 | \item \textbf{"Software Testing Tutorial"} on Coursera 144 | \begin{itemize} 145 | \item A broader perspective on software testing, with methodologies that can be applied to Dart and Flutter. 146 | \end{itemize} 147 | 148 | \item \textbf{"Advanced Flutter Architectures"} on Udemy 149 | \begin{itemize} 150 | \item Focuses on building scalable and testable Flutter applications, emphasizing best practices. 151 | \end{itemize} 152 | \end{enumerate} 153 | 154 | \subsection*{Conclusion} 155 | 156 | Books and courses provide structured paths to mastery. 157 | While the official documentation remains a vital resource, these curated materials offer additional perspectives, examples, and methodologies. 158 | As always, it's crucial to practice as you learn, implementing the concepts in real-world projects to solidify your understanding. 159 | 160 | 161 | 162 | \subsection{Related Communities and Forums for Dart, Flutter, and Testing Enthusiasts} 163 | 164 | Engaging with the community is one of the most effective ways to grow as a developer. 165 | By joining forums and online communities, you get the chance to share your knowledge, ask questions, learn from others' experiences, and stay updated with the latest trends and best practices. 166 | Below is a curated list of communities and forums related to Dart, Flutter, and testing. 167 | 168 | \subsection*{1. Dart and Flutter Communities} 169 | 170 | \subsubsection*{Reddit} 171 | 172 | \begin{itemize} 173 | \item \fakelinklistitem{r/dartlang}{https://www.reddit.com/r/dartlang/}{Dedicated to the Dart language, its frameworks, and tools.} 174 | \item \fakelinklistitem{r/FlutterDev}{https://www.reddit.com/r/FlutterDev/}{A bustling community of Flutter enthusiasts sharing projects, news, and tutorials.} 175 | \end{itemize} 176 | 177 | \subsubsection*{Stack Overflow} 178 | 179 | \begin{itemize} 180 | \item \fakelinklistitem{Dart Tag}{https://stackoverflow.com/questions/tagged/dart}{A tag dedicated to Dart-related questions.} 181 | \item \fakelinklistitem{Flutter Tag}{https://stackoverflow.com/questions/tagged/flutter}{A place where developers ask and answer questions about Flutter.} 182 | \end{itemize} 183 | 184 | \subsubsection*{Discord} 185 | 186 | \begin{itemize} 187 | \item \fakelinklistitem{Flutter Community}{https://discord.com/invite/N7Yshp4}{An active server with discussions about all things Flutter.} 188 | \end{itemize} 189 | 190 | \subsection*{2. Testing Communities} 191 | 192 | \subsubsection*{Reddit} 193 | 194 | \begin{itemize} 195 | \item \fakelinklistitem{r/softwaretesting}{https://www.reddit.com/r/softwaretesting/}{A community dedicated to software testing, methodologies, tools, and best practices.} 196 | \end{itemize} 197 | 198 | \subsubsection*{Stack Overflow} 199 | 200 | \begin{itemize} 201 | \item \fakelinklistitem{Unit Testing Tag}{https://stackoverflow.com/questions/tagged/unit-testing}{Questions and discussions about unit testing across various languages, including Dart.} 202 | \end{itemize} 203 | 204 | \subsubsection*{Ministry of Testing} 205 | 206 | \begin{itemize} 207 | \item \fakelinklistitem{Community}{https://www.ministryoftesting.com/}{A massive community of testers with a plethora of resources, events, and forums dedicated to software testing.} 208 | \end{itemize} 209 | 210 | \subsection*{3. General Tech and Developer Communities} 211 | 212 | \begin{itemize} 213 | \item \fakelinklistitem{Dev.to}{https://dev.to/}{A platform where developers share articles, tutorials, and discussions. Search for \incode{#dart} or \incode{#flutter} to find related content.} 214 | \item \fakelinklistitem{Hashnode}{https://hashnode.com/}{Another developer-centric platform with tons of Flutter and Dart content.} 215 | \end{itemize} 216 | 217 | \subsection*{4. Local Meetups} 218 | 219 | \begin{itemize} 220 | \item \fakelinklistitem{Meetup.com}{https://www.meetup.com/}{Search for local Dart and Flutter meetups in your city or region. These are great for networking and learning from local experts.} 221 | \end{itemize} 222 | 223 | \subsection*{Conclusion} 224 | 225 | Communities and forums are a goldmine for knowledge and networking. 226 | They offer real-world insights, provide solutions to common problems, and most importantly, give a sense of belonging to a global family of developers and testers. 227 | -------------------------------------------------------------------------------- /tex/ch6-special-topics.tex: -------------------------------------------------------------------------------- 1 | \section{Special Topics} 2 | 3 | \subsection{Test-Driven Development (TDD) in Dart} 4 | 5 | Test-Driven Development (TDD) is a software development methodology where tests are written before the actual code, leading to cleaner, more maintainable, and bug-resistant code. Here, we'll discuss the ins and outs of TDD in Dart development. 6 | 7 | \subsection*{1. Introduction to TDD} 8 | 9 | TDD revolves around a short and iterative development cycle. The developer: 10 | 11 | \begin{enumerate} 12 | \item Writes a failing test. 13 | \item Writes the minimal code to make the test pass. 14 | \item Refactors the code for optimization and clarity, ensuring tests still pass. 15 | \end{enumerate} 16 | 17 | \subsection*{2. Benefits of TDD} 18 | 19 | \begin{itemize} 20 | \item \textbf{Higher Code Quality}: Catch issues early in development. 21 | \item \textbf{Improved Design}: Code evolves organically, leading to better architecture. 22 | \item \textbf{Confidence}: Changes can be made without fearing unintended consequences. 23 | \item \textbf{Documentation}: Tests act as a documentation source, showing how a system should behave. 24 | \end{itemize} 25 | 26 | \subsection*{3. TDD Cycle in Dart} 27 | 28 | \subsubsection*{1. Write a Failing Test} 29 | 30 | Start by thinking about what the function or feature should do and then write a test for that. 31 | 32 | \begin{dartcode} 33 | void main() { 34 | test('should return the square of a number', () { 35 | final result = square(5); 36 | expect(result, equals(25)); 37 | }); 38 | } 39 | \end{dartcode} 40 | 41 | This test will fail because we haven't defined the `square` function yet. 42 | 43 | \subsubsection*{2. Implement the Functionality} 44 | 45 | Write just enough code to make the test pass: 46 | 47 | \begin{dartcode} 48 | int square(int number) { 49 | return number * number; 50 | } 51 | \end{dartcode} 52 | 53 | \subsubsection*{3. Refactor} 54 | 55 | If you see any opportunity to improve the code without altering its behavior, do it now: 56 | 57 | \begin{dartcode} 58 | int square(int number) => number * number; 59 | \end{dartcode} 60 | 61 | \subsection*{4. Common TDD Practices in Dart} 62 | 63 | \begin{itemize} 64 | \item \textbf{Mocking}: Use Dart's mockito package to mock dependencies and focus on testing the unit at hand. 65 | \item \textbf{Red-Green-Refactor}: Remember the TDD cycle – first the test fails (Red), then make it pass (Green), and finally refactor. 66 | \item \textbf{Continuous Integration}: Run tests on every code change using CI tools to ensure no regression. 67 | \end{itemize} 68 | 69 | \subsection*{5. Challenges in TDD} 70 | 71 | \begin{itemize} 72 | \item \textbf{Initial Overhead}: TDD can feel slower at the start. 73 | \item \textbf{Learning Curve}: It requires a shift in mindset from traditional coding. 74 | \item \textbf{Over-reliance}: Not every tiny piece of code needs to be driven by tests. Balance is key. 75 | \end{itemize} 76 | 77 | \subsection*{6. TDD with Flutter} 78 | 79 | In Flutter, TDD can be employed to create widget tests and integration tests: 80 | 81 | \begin{enumerate} 82 | \item Create a widget test to verify a certain UI state or behavior. 83 | \item Build the widget to satisfy the test. 84 | \item Refactor if needed, ensuring the test remains green. 85 | \end{enumerate} 86 | 87 | \subsection*{Conclusion} 88 | 89 | TDD is a powerful methodology that can significantly elevate the quality of your Dart and Flutter applications. 90 | While it requires a bit of initial investment and a change in mindset, the benefits in terms of code reliability, maintainability, and overall quality are immense. 91 | 92 | In the subsequent sections, we'll dive deeper into practical TDD scenarios, explore tools that can aid TDD in Dart, and investigate advanced TDD strategies for scalable applications. 93 | 94 | 95 | 96 | \subsection{Behavior-Driven Development (BDD) in Dart} 97 | 98 | Behavior-Driven Development (BDD) extends the principles of Test-Driven Development (TDD) by emphasizing collaboration between developers, QA, and non-technical participants. 99 | It focuses on defining the expected behavior of a system from the user's perspective. 100 | Let's delve into the concept of BDD within Dart and Flutter applications. 101 | 102 | \subsection*{1. What is BDD?} 103 | 104 | BDD bridges the gap between technical and non-technical stakeholders by using plain language specifications to describe software behavior. 105 | These specifications are then translated into tests. 106 | 107 | \subsection*{2. Advantages of BDD} 108 | 109 | \begin{itemize} 110 | \item \textbf{Clearer Understanding}: Requirements are better understood since everyone is involved. 111 | \item \textbf{Reduced Ambiguity}: Plain language specifications reduce misunderstandings. 112 | \item \textbf{Focus on User Value}: Features are designed around user needs. 113 | \item \textbf{Living Documentation}: BDD specs act as up-to-date documentation. 114 | \end{itemize} 115 | 116 | \subsection*{3. BDD in Dart with Gherkin} 117 | 118 | \incode{flutter_gherkin} is a popular tool for BDD, and there's a Dart implementation named \incode{gherkin} that allows writing BDD-style tests in Dart. 119 | 120 | \fakesubsection{Example BDD Workflow:} 121 | 122 | \begin{enumerate} 123 | \item \textbf{Define a Feature} \\ 124 | In a \incode{.feature} file, describe the behavior: 125 | \begin{yamlcode} 126 | Feature: Square a number 127 | As a mathematician 128 | I want to square numbers 129 | So that I can obtain the product of a number with itself. 130 | \end{yamlcode} 131 | 132 | \item \textbf{Write Scenarios} \\ 133 | Scenarios outline specific instances of the feature: 134 | 135 | \begin{yamlcode} 136 | Scenario: Squaring a positive number 137 | Given I have the number 5 138 | When I square the number 139 | Then I should get 25 140 | \end{yamlcode} 141 | 142 | \item \textbf{Implement Step Definitions} 143 | Now, using Dart and gherkin, implement the steps: 144 | 145 | \begin{dartcode} 146 | Given('I have the number {int}', (int number) async { 147 | // Store the number for the next steps. 148 | }); 149 | 150 | When('I square the number', () async { 151 | // Square the number. 152 | }); 153 | 154 | Then('I should get {int}', (int expected) async { 155 | // Assert the squared result. 156 | }); 157 | \end{dartcode} 158 | \end{enumerate} 159 | 160 | \subsection*{4. BDD and Flutter} 161 | 162 | For Flutter, BDD can help in defining UI/UX behavior and interactions. 163 | You can use packages like \incode{flutter_gherkin} to implement BDD-style tests for Flutter applications. 164 | 165 | \begin{enumerate} 166 | \item Define the feature and scenarios in \incode{.feature} files. 167 | \item Write step definitions using Flutter's testing framework to interact with widgets and verify behavior. 168 | \end{enumerate} 169 | 170 | \subsection*{5. Challenges and Considerations} 171 | 172 | \begin{itemize} 173 | \item \textbf{Learning Curve}: Understanding and setting up BDD tools can take time. 174 | \item \textbf{Maintaining Specs}: As with any test, keeping BDD specs up-to-date is crucial. 175 | \item \textbf{Avoid Over-Specification}: Focus on key behaviors and avoid writing specs for trivial features. 176 | \end{itemize} 177 | 178 | \subsection*{Conclusion} 179 | 180 | BDD is a powerful approach, especially for projects where clear communication between stakeholders is critical. 181 | By focusing on user behavior, Dart and Flutter developers can create more user-centric applications. 182 | 183 | 184 | \subsection{Performance Testing in Dart and Flutter} 185 | 186 | Performance is a crucial factor that can significantly influence user satisfaction and retention. While functional correctness ensures an application does what it's supposed to, performance testing verifies that the application does so in an acceptable time, without consuming excessive resources. Let's explore performance testing in Dart and Flutter. 187 | 188 | \subsection*{1. What is Performance Testing?} 189 | 190 | Performance testing is a type of testing aimed at determining a system's responsiveness and stability under a particular workload. 191 | It can also serve to identify bottlenecks, establish baselines, and ensure compliance with performance criteria. 192 | 193 | \subsection*{2. Types of Performance Testing} 194 | 195 | \begin{itemize} 196 | \item Load Testing: Assess system behavior under anticipated peak load conditions. 197 | \item Stress Testing: Evaluate system robustness beyond normal operational capacity, often to the point of failure. 198 | \item Endurance Testing: Analyze system performance under expected load over an extended period. 199 | \item Spike Testing: Investigate reactions to sudden, large spikes in load. 200 | \item Scalability Testing: Determine the system's capacity to scale when additional resources are added. 201 | \end{itemize} 202 | 203 | \subsection*{3. Performance Testing in Dart} 204 | 205 | In Dart, especially for backend services, you might focus on: 206 | 207 | \begin{itemize} 208 | \item \textbf{Response Times}: The time it takes to respond to requests. 209 | \item \textbf{Throughput}: The number of requests handled per unit of time. 210 | \item \textbf{Resource Utilization}: How efficiently resources (like CPU, memory) are used. 211 | \end{itemize} 212 | Tools like \incode{benchmark_harness} can be valuable for Dart VM benchmarks. 213 | 214 | \subsection*{4. Performance Testing in Flutter} 215 | 216 | Flutter offers a rich set of tools and libraries to help in performance testing: 217 | 218 | \begin{itemize} 219 | \item \textbf{Flutter Driver}: Allows for the creation of performance tests as part of integration tests. 220 | \item \textbf{Widget-level Benchmarks}: Using \incode{benchmark_harness} package, you can perform benchmarks for widgets. 221 | \item \textbf{PerformanceOverlay}: A Flutter widget that displays performance metrics. 222 | \end{itemize} 223 | 224 | \fakesubsection{Key Focus Areas in Flutter:} 225 | 226 | \begin{itemize} 227 | \item \textbf{Frame Building Times}: Ensure the smooth rendering of animations. 228 | \item \textbf{CPU \& Memory Usage}: Monitor resource consumption, especially during animations or complex operations. 229 | \item \textbf{Startup Time}: Measure the time taken from app launch to readiness for user input. 230 | \end{itemize} 231 | 232 | \subsection*{5. Analyzing Results} 233 | 234 | After running tests: 235 | 236 | \begin{itemize} 237 | \item \textbf{Set Baselines}: Understand normal performance metrics to quickly identify deviations in the future. 238 | \item \textbf{Identify Bottlenecks}: Prioritize issues that significantly degrade performance. 239 | \item \textbf{Optimize}: Make necessary code or architecture adjustments. 240 | \item \textbf{Re-test}: Confirm that optimizations have the desired effect without introducing new issues. 241 | \end{itemize} 242 | 243 | \subsection*{6. Challenges in Performance Testing} 244 | 245 | \begin{itemize} 246 | \item \textbf{Environmental Differences}: Discrepancies between testing and production environments can lead to inaccurate results. 247 | \item \textbf{Dynamic Behavior}: User behavior can be unpredictable, making it hard to emulate realistic conditions. 248 | \item \textbf{Interdependencies}: External systems, such as databases or APIs, can influence performance. 249 | \end{itemize} 250 | 251 | \subsection*{Conclusion} 252 | 253 | Performance testing is an essential discipline in software development. 254 | For Dart and Flutter developers, it ensures that applications and services not only meet functional requirements but also deliver a seamless, efficient user experience. 255 | 256 | In upcoming sections, we'll provide a deeper dive into tools, best practices, and advanced techniques to master performance testing in Dart and Flutter. 257 | 258 | 259 | 260 | 261 | 262 | 263 | 264 | 265 | 266 | 267 | -------------------------------------------------------------------------------- /tex/ch5-test-tips-and-best-practices.tex: -------------------------------------------------------------------------------- 1 | \section{Testing Tips and Best Practices} 2 | \subsection{Organizing Test Code in Flutter} 3 | 4 | Clean, structured, and organized test code is as important as the main codebase. Not only does it make tests more maintainable, but it also ensures that others can understand and contribute easily. This guide will delve into best practices for organizing your test code in Flutter. 5 | 6 | \subsection*{1. Directory Structure} 7 | 8 | Follow a consistent directory structure that mirrors your main codebase. For instance: 9 | 10 | \begin{yamlcode} 11 | my_app/ 12 | |-- lib/ 13 | | |-- src/ 14 | | | |-- models/ 15 | | | |-- views/ 16 | | | |-- controllers/ 17 | |-- test/ 18 | | |-- unit/ 19 | | | |-- models/ 20 | | | |-- controllers/ 21 | | |-- widget/ 22 | | | |-- views/ 23 | | |-- integration/ 24 | \end{yamlcode} 25 | 26 | By mirroring the structure, locating corresponding test files becomes intuitive. 27 | 28 | \subsection*{2. File Naming Convention} 29 | 30 | Naming conventions make it clear at a glance what a file contains. A common approach is to use the name of the component being tested followed by \incode{_test}. 31 | 32 | \begin{yamlcode} 33 | user_model_test.dart 34 | login_page_test.dart 35 | \end{yamlcode} 36 | 37 | \subsection*{3. Use of setUp and tearDown} 38 | 39 | These functions, provided by the \incode{test} package, are useful for setting up initial configurations and cleaning up resources after each test. 40 | 41 | \begin{dartcode} 42 | setUp(() { 43 | // Initialization code here 44 | }); 45 | 46 | tearDown(() { 47 | // Cleanup code here 48 | }); 49 | \end{dartcode} 50 | 51 | \subsection*{4. Grouping Tests} 52 | 53 | Use the \incode{group} function to logically group related tests, making them more readable and organized. 54 | 55 | \begin{dartcode} 56 | group('Login Tests', () { 57 | test('Valid credentials', () {...}); 58 | test('Invalid credentials', () {...}); 59 | }); 60 | \end{dartcode} 61 | 62 | \subsection*{5. Mocking \& Dependency Separation} 63 | 64 | Place mocks and fakes in a separate directory or file. This makes it clear which components are real and which are mocked, plus promotes reuse across tests. 65 | 66 | \begin{yamlcode} 67 | test/ 68 | |-- mocks/ 69 | | |-- mock_user_service.dart 70 | \end{yamlcode} 71 | 72 | \subsection*{6. Shared Test Utilities} 73 | 74 | If you have utility functions or shared setup code for multiple tests, consider moving them into shared files. 75 | 76 | \begin{yamlcode} 77 | test/ 78 | |-- utils/ 79 | | |-- test_helpers.dart 80 | \end{yamlcode} 81 | 82 | \subsection*{7. Comments \& Documentation} 83 | 84 | Just like your main code, comments can be beneficial in tests, especially when dealing with complex scenarios or edge cases. 85 | 86 | \begin{dartcode} 87 | // Testing edge case where user has no active subscription 88 | test('User without subscription', () {...}); 89 | \end{dartcode} 90 | 91 | \subsection*{8. Keep Tests DRY (Don't Repeat Yourself)} 92 | 93 | If a piece of setup or assertion logic is repeated across multiple tests, consider factoring it out into a separate function. 94 | 95 | \subsection*{9. Isolate Unit, Widget, and Integration Tests} 96 | 97 | Separate these tests into distinct directories to ensure clarity and prevent accidental mix-ups. 98 | 99 | \subsection*{Conclusion} 100 | 101 | Organizing test code might seem like a chore initially, but it's an investment that pays off manifold in the long run. As your project grows, structured and organized tests will make maintenance easier, reduce bugs, and help onboard new developers faster. 102 | 103 | In the upcoming sections, we'll dive deeper into advanced testing topics, explore tools and plugins to aid your testing journey, and examine case studies of effective test strategies. 104 | 105 | 106 | \subsection{Continuous Integration with Dart and Flutter} 107 | 108 | Continuous Integration (CI) is the practice of merging code changes frequently to the main branch and validating them automatically with tests. When combined with Dart and Flutter applications, CI can ensure consistent code quality and reduce the chances of introducing bugs. This guide provides insights into setting up CI for Dart and Flutter projects. 109 | 110 | \subsection*{1. Benefits of CI for Dart Projects} 111 | 112 | \begin{itemize} 113 | \item \textbf{Automated Testing}: Automatically run unit, widget, and integration tests to catch issues early. 114 | \item \textbf{Consistent Code Quality}: Ensure code adheres to style guidelines and lint rules. 115 | \item \textbf{Early Bug Detection}: Identify and rectify issues before they reach the production environment. 116 | \item \textbf{Streamlined Deployments}: Automate the deployment process of applications or packages. 117 | \end{itemize} 118 | 119 | \subsection*{2. Popular CI Tools for Dart and Flutter} 120 | 121 | \begin{itemize} 122 | \item \textbf{GitHub Actions}: Directly integrated with GitHub, it offers powerful workflows for Dart and Flutter. 123 | \item \textbf{Travis CI}: A popular CI solution with good support for Flutter apps. 124 | \item \textbf{CircleCI}: Known for its speed and customizability; it also supports Flutter projects. 125 | \item \textbf{GitLab CI}: If you're using GitLab, its inbuilt CI/CD tools are highly versatile. 126 | \end{itemize} 127 | 128 | \subsection*{3. Setting up CI} 129 | 130 | \fakesubsection{Example with GitHub Actions} 131 | 132 | \begin{enumerate} 133 | \item In your repository, create a \incode{.github/workflows} directory. 134 | \item Inside, create a file named \incode{dart_ci.yml} or similar. 135 | \item Define your CI steps: 136 | \end{enumerate} 137 | 138 | \begin{yamlcode} 139 | name: Dart CI 140 | 141 | on: [push, pull_request] 142 | 143 | jobs: 144 | build: 145 | runs-on: ubuntu-latest 146 | steps: 147 | - uses: actions/checkout@v2 148 | - uses: actions/setup-dart@v1 149 | with: 150 | channel: 'stable' 151 | - run: dart pub get 152 | - run: dart analyze 153 | - run: dart test 154 | \end{yamlcode} 155 | 156 | This workflow installs Dart, gets the dependencies, analyzes the code for linting errors, and runs the tests. 157 | 158 | \subsection*{4. Handling Dependencies} 159 | 160 | Caching dependencies can speed up CI build times. Most CI systems provide caching mechanisms. For instance, with GitHub Actions, you can cache the \incode{.pub-cache} directory to speed up subsequent builds. 161 | 162 | \subsection*{5. Flutter-specific CI Tasks} 163 | 164 | For Flutter, you might want to: 165 | 166 | \begin{itemize} 167 | \item Build the app for specific platforms (iOS, Android, web, etc.). 168 | \item Run widget tests in headless mode. 169 | \item Use \incode{flutter drive} for integration tests. 170 | \item Adjust your CI configuration accordingly. 171 | \end{itemize} 172 | 173 | \subsection*{6. Automate Deployments (Optional)} 174 | 175 | You can extend CI to Continuous Deployment (CD). For instance, upon merging to the main branch, your CI system could: 176 | 177 | \begin{itemize} 178 | \item Deploy a web app to hosting platforms like Firebase Hosting. 179 | \item Publish a package to \incode{pub.dev}. 180 | \item Build and upload mobile app binaries to app stores. 181 | \end{itemize} 182 | 183 | 184 | \subsection*{Conclusion} 185 | 186 | Implementing CI for Dart and Flutter projects amplifies the benefits of testing, linting, and other quality measures, ensuring that they are consistently applied. While there's an initial overhead in setting up CI, the long-term advantages in terms of code quality, developer productivity, and peace of mind are immeasurable. 187 | 188 | In the next sections, we'll deep-dive into advanced CI/CD techniques, explore best practices in the context of Dart and Flutter, and showcase real-world CI/CD workflows. 189 | 190 | \subsection{Common Testing Pitfalls in Dart and Flutter and How to Avoid Them} 191 | 192 | While testing is an integral part of the software development process, it's not immune to challenges and pitfalls. Here, we'll outline some common mistakes developers might encounter and provide solutions to avoid them. 193 | 194 | \subsection*{1. Flaky Tests} 195 | 196 | \subsubsection*{Pitfall:} 197 | Tests intermittently pass or fail without any apparent changes to the code. 198 | 199 | \subsubsection*{Solution:} 200 | 201 | \begin{itemize} 202 | \item Ensure there's no dependency on external factors like time, random number generation, or network. 203 | \item Avoid using \incode{pumpAndSettle} indiscriminately in widget tests. 204 | \item Check if asynchronous code is correctly handled in tests. 205 | \end{itemize} 206 | 207 | \subsection*{2. Overmocking} 208 | 209 | \subsubsection*{Pitfall:} 210 | 211 | Replacing too many real implementations with mocks, making tests pass even when the real implementation is broken. 212 | 213 | \subsubsection*{Solution:} 214 | 215 | \begin{itemize} 216 | \item Mock only the parts that are absolutely necessary, like external services. 217 | \item Occasionally run tests with real implementations to verify their accuracy. 218 | \end{itemize} 219 | 220 | \subsection*{3. Testing Implementation Instead of Behavior} 221 | 222 | \subsubsection*{Pitfall:} 223 | 224 | Writing tests that are overly tied to the implementation details, causing them to break when refactoring. 225 | 226 | \subsubsection*{Solution:} 227 | 228 | \begin{itemize} 229 | \item Write tests based on the expected behavior or outcome. 230 | \item Avoid relying on internal state unless it's directly related to the test's objective. 231 | \end{itemize} 232 | 233 | \subsection*{4. Not Testing Edge Cases} 234 | 235 | \subsubsection*{Pitfall:} 236 | 237 | Only testing the "happy path" and neglecting potential edge cases or error scenarios. 238 | 239 | \subsubsection*{Solution:} 240 | 241 | \begin{itemize} 242 | \item Identify potential edge cases through brainstorming or tools. 243 | \item Use techniques like boundary value analysis or decision tables. 244 | \end{itemize} 245 | 246 | \subsection*{5. Ignoring Test Failures} 247 | 248 | \subsubsection*{Pitfall:} 249 | 250 | Over time, a few failing tests are ignored, assuming they aren't important. 251 | 252 | \subsubsection*{Solution:} 253 | 254 | \begin{itemize} 255 | \item Treat every test failure as a potential issue. 256 | \item If a test is consistently failing without reason, consider revisiting its logic. 257 | \end{itemize} 258 | 259 | \subsection*{6. Large and Complicated Test Setups} 260 | 261 | \subsubsection*{Pitfall:} 262 | 263 | Setting up a complex environment for each test, making it hard to understand and maintain. 264 | 265 | \subsubsection*{Solution:} 266 | 267 | \begin{itemize} 268 | \item Use setUp and tearDown for common setups and clean-ups. 269 | \item Break down complex setups into smaller, reusable functions. 270 | \end{itemize} 271 | 272 | \subsection*{7. Not Using Continuous Integration} 273 | 274 | \subsubsection*{Pitfall:} 275 | 276 | Not getting feedback on tests from an environment similar to production. 277 | 278 | \subsubsection*{Solution:} 279 | 280 | \begin{itemize} 281 | \item Integrate a CI system to run tests automatically on every code change. 282 | \item Ensure the CI environment mirrors the production environment as closely as possible. 283 | \end{itemize} 284 | 285 | \subsection*{8. Lack of Test Documentation} 286 | 287 | \subsubsection*{Pitfall:} 288 | 289 | Other developers struggle to understand the purpose or context of tests. 290 | 291 | \subsubsection*{Solution:} 292 | 293 | \begin{itemize} 294 | \item Use clear and descriptive test names. 295 | \item Comment complex or non-intuitive parts of test code. 296 | \end{itemize} 297 | 298 | \subsection*{Conclusion} 299 | 300 | Every developer, regardless of experience, can fall into the trap of these pitfalls. Recognizing and addressing them early ensures that your test suite remains a valuable asset rather than becoming a liability. With the insights shared above, you'll be better equipped to create and maintain effective, reliable tests for your Dart and Flutter projects. 301 | 302 | -------------------------------------------------------------------------------- /tex/ch3-widget-tests.tex: -------------------------------------------------------------------------------- 1 | \section{Widget Tests} 2 | 3 | \subsection{Introduction to Widget Tests in Flutter} 4 | While unit tests verify the correctness of individual units of code, widget tests (also known as component tests) assess individual widgets in isolation. 5 | Given that widgets are the central building blocks of Flutter applications, ensuring their correct behavior and rendering is essential. 6 | In this section, we will introduce the basics of widget testing in Flutter. 7 | 8 | \subsection*{What are Widget Tests?} 9 | 10 | In Flutter, everything from a button to a screen is a widget. 11 | Widget tests ensure that each of these widgets behaves and appears as expected when interacted with. 12 | Instead of running the full app, widget tests focus on a single widget, making them more efficient than full app tests but more comprehensive than unit tests. 13 | 14 | \subsection*{Setting Up} 15 | 16 | To write widget tests, you need the \incode{flutter_test} package, which is typically included in the \incode{dev_dependencies} section of your \incode{pubspec.yaml} file: 17 | 18 | \begin{yamlcode} 19 | dev_dependencies: 20 | flutter_test: 21 | sdk: flutter 22 | \end{yamlcode} 23 | 24 | \subsection*{Writing a Basic Widget Test} 25 | \fakesubsection{1. Import Necessary Libraries} 26 | At the beginning of your test file: 27 | \begin{dartcode} 28 | import 'package:flutter_test/flutter_test.dart'; 29 | import 'package:your_app/path_to_your_widget.dart'; 30 | \end{dartcode} 31 | 32 | \fakesubsection{2. Write the Test} 33 | Widget tests use the testWidgets function. Here's an example of testing a simple \incode{RaisedButton}: 34 | 35 | \begin{dartcode} 36 | void main() { 37 | testWidgets('Renders a raised button', (WidgetTester tester) async { 38 | // Build our app and trigger a frame. 39 | await tester.pumpWidget(MaterialApp(home:RaisedButton(onPressed: () {}, child: Text('Click me')))); 40 | 41 | // Verify if the button is displayed. 42 | expect(find.byType(RaisedButton), findsOneWidget); 43 | expect(find.text('Click me'), findsOneWidget); 44 | }); 45 | } 46 | \end{dartcode} 47 | 48 | \fakesubsection{3. Run the Test} 49 | Use the command: 50 | \begin{bashcode} 51 | flutter test path_to_your_test_file.dart 52 | \end{bashcode} 53 | 54 | \subsection*{Interacting with Widgets in Tests} 55 | \incode{WidgetTester} provides a multitude of methods to simulate interactions: 56 | 57 | \begin{itemize} 58 | \item \textbf{Tap}: \incode{tester.tap(find.byType(RaisedButton));} 59 | \item \textbf{Drag}: \incode{tester.drag(find.byType(ListView), Offset(0, -200));} 60 | \item \textbf{Enter Text}: \incode{tester.enterText(find.byType(TextField), 'Hello Flutter');} 61 | \end{itemize} 62 | After any interaction, you typically call \textbf{tester.pump()} to rebuild the widget tree and reflect changes. 63 | 64 | \subsection*{Benefits of Widget Tests} 65 | \begin{enumerate} 66 | \item \textbf{Confidence}: Ensure that changes or refactors don't break your UI. 67 | \item \textbf{Speed}: Faster than full app integration tests since they don't involve the entire system. 68 | \item \textbf{Documentation}: They serve as documentation, showcasing how a widget is expected to behave and look. 69 | \end{enumerate} 70 | 71 | \subsection*{Conclusion} 72 | Widget tests are an invaluable tool in the Flutter developer's toolkit. 73 | They bridge the gap between unit tests and full app integration tests, offering a middle ground that validates the UI's correctness without the overhead of running the entire app. 74 | 75 | As you delve deeper into Flutter development, harnessing the power of widget tests will be crucial in building robust, bug-free apps. 76 | 77 | In the next sections, we'll explore advanced techniques and best practices in widget testing. 78 | 79 | Stay tuned! 80 | 81 | \subsection{Mocking Widgets in Flutter} 82 | 83 | Testing widgets often requires simulating certain behaviors or states that are normally triggered by backend data, user inputs, or other external factors. 84 | In many cases, directly interacting with these external factors is either challenging or counterproductive. 85 | That's where mocking comes into play. 86 | This section provides insights into mocking widgets and their dependencies in Flutter. 87 | 88 | \subsection*{The Need for Mocking in Widget Tests} 89 | Here are some common scenarios where mocking can be beneficial: 90 | 91 | \begin{enumerate} 92 | \item \textbf{External Dependencies}: Such as API calls, database operations, or third-party services. 93 | \item \textbf{User Inputs}: Simulating specific user behaviors without manual intervention. 94 | \item \textbf{Specific States}: Testing how a widget behaves under specific conditions, like error states or empty data. 95 | \end{enumerate} 96 | 97 | \subsection*{Using mockito with Flutter} 98 | \incode{mockito}, which you might be familiar with from Dart unit tests, also plays a crucial role in widget tests. 99 | The primary difference lies in how it's used in the context of Flutter's widgets. 100 | 101 | \subsection*{Mocking Providers or Services} 102 | Imagine you have a widget that fetches user data from an API. 103 | You'd likely have a service or provider that manages this. 104 | To test the widget in isolation, you'd mock this service or provider. 105 | 106 | For a \incode{UserService} that fetches user data: 107 | 108 | \begin{dartcode} 109 | class UserService { 110 | Future fetchUser(int id) { 111 | // logic to fetch user from API 112 | } 113 | } 114 | \end{dartcode} 115 | Using \incode{mockito}, create a mock: 116 | \begin{dartcode} 117 | class MockUserService extends Mock implements UserService {} 118 | \end{dartcode} 119 | 120 | In your widget test, you can then provide this mock service to your widget using a provider or dependency injection. 121 | 122 | \subsection*{Simulating Responses} 123 | With the mock service in place, you can dictate its behavior: 124 | \begin{dartcode} 125 | final userService = MockUserService(); 126 | 127 | // Mock a successful user fetch 128 | when(userService.fetchUser(1)).thenAnswer((_) async => User(id: 1, name: 'John Doe')); 129 | \end{dartcode} 130 | 131 | \subsection*{Mocking Widgets} 132 | Sometimes, it might be useful to mock entire widgets, especially if they have intricate behaviors or external dependencies themselves. 133 | You can achieve this by creating a stub or mock widget to replace the actual widget in tests. 134 | 135 | For instance, if you have a custom \incode{MapWidget} that displays a map and you want to avoid rendering it in certain tests, you could replace it with a simpler Placeholder widget. 136 | 137 | \subsection*{Testing with Mocked Data} 138 | Once your mocks are set up, you can test how your widget reacts to various data scenarios: 139 | \begin{dartcode} 140 | testWidgets('Displays user data', (WidgetTester tester) async { 141 | // Use the mocked data setup 142 | await tester.pumpWidget(MyApp(userService: userService)); 143 | 144 | // Check if the user data is displayed 145 | expect(find.text('John Doe'), findsOneWidget); 146 | }); 147 | \end{dartcode} 148 | 149 | \subsection*{Handling Streams and Change Notifiers} 150 | Mocking streams or ChangeNotifier classes requires a bit more setup, but the principle is the same. Using mockito, you can mock the stream or methods on the ChangeNotifier and then check how the widget reacts. 151 | 152 | \subsection*{Conclusion} 153 | Mocking is an invaluable technique when testing widgets in Flutter. 154 | By simulating different data states, user interactions, and external dependencies, you can ensure your widgets are robust and handle various scenarios gracefully. 155 | As you continue building more complex apps, these testing techniques will become an essential part of your development workflow. 156 | 157 | Up next, delve deeper into advanced widget testing and explore how to test complex UI interactions and flows. 158 | 159 | 160 | \subsection{Testing Individual Widgets in Flutter} 161 | As you venture into the world of Flutter, you'll quickly realize the importance of widgets. 162 | They are the building blocks of your application. 163 | Testing them ensures that each visual and functional element works as expected. 164 | This chapter focuses on the specifics of testing individual widgets. 165 | 166 | \subsection*{Why Test Individual Widgets?} 167 | 168 | \begin{itemize} 169 | \item \textbf{Precision}: Targets specific widget behaviors without the noise from surrounding elements. 170 | \item \textbf{Speed}: Faster execution as you're not testing the entire screen or app. 171 | \item \textbf{Isolation}: Ensures that any bugs or issues are isolated to the widget itself. 172 | \end{itemize} 173 | 174 | \subsection*{Getting Started} 175 | 176 | To test individual widgets, you'll need the flutter\_test package. It offers tools like testWidgets for running widget tests and WidgetTester for interacting with widgets. 177 | 178 | \begin{yamlcode} 179 | dev_dependencies: 180 | flutter_test: 181 | sdk: flutter 182 | \end{yamlcode} 183 | 184 | \subsection*{Basic Widget Test} 185 | The essence of a widget test is to: 186 | \begin{enumerate} 187 | \item Create the widget. 188 | \item Add it to the widget tree. 189 | \item Interact with it or check its state. 190 | \item Verify that it behaves and renders as expected. 191 | \end{enumerate} 192 | 193 | \subsubsection*{Example: Testing a Text Widget} 194 | 195 | \begin{dartcode} 196 | void main() { 197 | testWidgets('Displays the correct text', (WidgetTester tester) async { 198 | await tester.pumpWidget(Text('Hello, Flutter!')); 199 | 200 | expect(find.text('Hello, Flutter!'), findsOneWidget); 201 | }); 202 | } 203 | \end{dartcode} 204 | 205 | \subsection*{Interactions and Assertions} 206 | 207 | \incode{WidgetTester} allows you to simulate different interactions like tapping, dragging, and typing. After an interaction, use assertions to check the widget's state. 208 | 209 | \subsubsection*{Example: Testing a RaisedButton} 210 | 211 | \begin{dartcode} 212 | void main() { 213 | testWidgets('Tap on RaisedButton', (WidgetTester tester) async { 214 | bool wasPressed = false; 215 | 216 | await tester.pumpWidget( 217 | MaterialApp( 218 | home: RaisedButton( 219 | onPressed: () => wasPressed = true, 220 | child: Text('Tap me!'), 221 | ), 222 | ), 223 | ); 224 | 225 | await tester.tap(find.byType(RaisedButton)); 226 | await tester.pump(); 227 | 228 | expect(wasPressed, true); 229 | }); 230 | } 231 | \end{dartcode} 232 | 233 | \subsection*{Advanced Testing Techniques} 234 | 235 | \subsubsection*{Using Matchers} 236 | 237 | Matchers like \incode{findsNothing}, \incode{findsNWidgets(n)}, and \incode{findsWidgets} can help make your assertions more precise. For instance, to check that a widget doesn't exist, use \incode{expect(find.byType(MyWidget), findsNothing)}. 238 | 239 | \subsubsection*{Pumping Widgets} 240 | 241 | \incode{tester.pump()} triggers a rebuild of the widget tree, reflecting any state changes from the previous frame. In certain cases, you might need \incode{tester.pumpAndSettle()} which repeatedly calls \incode{pump} with the given duration until the widget tree is stable. 242 | 243 | \subsection*{Golden Tests} 244 | 245 | Golden tests (or snapshot tests) involve comparing the widget's rendering with a stored image (a golden file). 246 | This helps to check if the UI is rendered correctly and can be particularly useful for custom painted widgets. 247 | 248 | \begin{dartcode} 249 | await tester.pumpWidget(MyFancyWidget()); 250 | await expectLater(find.byType(MyFancyWidget), matchesGoldenFile('golden_file.png')); 251 | \end{dartcode} 252 | 253 | \subsection*{Conclusion} 254 | 255 | Testing individual widgets is a pivotal step in ensuring the robustness of your Flutter applications. 256 | Given the modular nature of Flutter's widget tree, having confidence in each building block is essential for the overall reliability of your app. 257 | 258 | In subsequent chapters, dive deeper into integration testing and explore how to ensure complete user flows and interactions are working harmoniously. 259 | 260 | \subsection{Advanced Widget Testing Topics in Flutter} 261 | 262 | After getting comfortable with basic widget testing, you may find a need to test more complex scenarios, or to optimize and refine your test suites. 263 | This chapter will explore advanced topics in widget testing to help you address more intricate challenges. 264 | 265 | \subsection*{Advanced Interactions} 266 | 267 | \subsubsection*{Long Press and Drag} 268 | 269 | `WidgetTester` offers methods for more complex interactions: 270 | 271 | \begin{dartcode} 272 | await tester.longPress(find.byType(MyWidget)); // Long press 273 | await tester.drag(find.byType(MyWidget), Offset(50, 50)); // Drag by an offset 274 | \end{dartcode} 275 | 276 | \subsubsection*{Multi-Touch Gestures} 277 | To simulate multi-touch gestures like pinch-to-zoom: 278 | 279 | \begin{dartcode} 280 | final firstLocation = tester.getCenter(find.byType(MyWidget)); 281 | final secondLocation = tester.getTopLeft(find.byType(MyWidget)); 282 | await tester.zoom(pinchStart: firstLocation, pinchEnd: secondLocation, scale: 2.5); 283 | \end{dartcode} 284 | 285 | \subsubsection*{Scrolling Widgets} 286 | 287 | To test widgets that scroll, like ListView or GridView: 288 | 289 | \begin{dartcode} 290 | await tester.scrollUntilVisible(find.text('item $index'), Offset(0, 500), scrollable: find.byType(Scrollable); // Scroll by an offset 291 | await tester.fling(find.byType(ListView), Offset(0, -500), 2500); // Fling/quick scroll 292 | await tester.pumpAndSettle(); 293 | \end{dartcode} 294 | 295 | \subsection*{Testing Animations} 296 | 297 | Animations might require additional considerations: 298 | 299 | \begin{itemize} 300 | \item \textbf{Pumping Frames}: To move forward in an animation, use \incode{tester.pump(Duration(milliseconds: x))}. 301 | \item \textbf{Evaluating States}: Check widget states at different points in an animation. 302 | \end{itemize} 303 | 304 | Example of testing a \incode{FadeTransition}: 305 | 306 | \begin{dartcode} 307 | final fadeTransition = FadeTransition(opacity: animationController, child: MyWidget()); 308 | await tester.pumpWidget(fadeTransition); 309 | 310 | expect(myWidgetFinder, findsOneWidget); 311 | 312 | // Begin the animation 313 | animationController.forward(); 314 | await tester.pumpAndSettle(); 315 | 316 | // Check after animation completes 317 | expect(myWidgetFinder, findsNothing); 318 | \end{dartcode} 319 | 320 | \subsubsection*{Custom Matchers} 321 | 322 | You can create custom matchers to help with more specific test conditions. For example, to check if a widget's size conforms to expected values: 323 | 324 | \begin{dartcode} 325 | Matcher hasSize(Size size) => MatchesWidgetData((widget) => widget.size == size); 326 | expect(find.byType(MyWidget), hasSize(Size(100, 100))); 327 | \end{dartcode} 328 | 329 | \subsubsection*{Working with Keys} 330 | 331 | Using keys, especially \incode{ValueKey}, can make finding widgets in tests much easier: 332 | 333 | \begin{dartcode} 334 | final myKey = ValueKey('my_widget_key'); 335 | MyWidget(key: myKey); 336 | \end{dartcode} 337 | 338 | In tests: 339 | \begin{dartcode} 340 | find.byKey(myKey); 341 | \end{dartcode} 342 | 343 | This can be especially helpful when differentiating between multiple instances of the same widget type. 344 | 345 | \subsubsection*{Grouping Tests} 346 | 347 | As your test suite grows, structuring your tests using groups can improve readability: 348 | 349 | \begin{dartcode} 350 | group('FlatButton Tests', () { 351 | testWidgets('Displays text', (WidgetTester tester) async { 352 | ... 353 | }); 354 | 355 | testWidgets('Handles onTap', (WidgetTester tester) async { 356 | ... 357 | }); 358 | }); 359 | \end{dartcode} 360 | 361 | \subsection*{Conclusion} 362 | 363 | Advanced widget testing in Flutter can seem complex, but by taking advantage of the rich set of tools provided by the framework, you can ensure your UI is robust and responds correctly under various scenarios. 364 | 365 | As you dive deeper into the testing ecosystem, remember that the balance between thorough testing and maintainability is crucial. 366 | Always aim for tests that are comprehensive yet flexible enough to adapt as your app evolves. 367 | 368 | Up next, venture into integration tests to explore comprehensive testing of full app flows and interactions! 369 | 370 | 371 | 372 | 373 | 374 | 375 | --------------------------------------------------------------------------------